,     .  //••; ,. 

AND  ITS 


W.H.  BOOTH 


LIQUID     FUEL 

AND    ITS    APPARATUS 


LIQUID     FUEL 

AND    ITS    APPARATUS 


By  WM.  H.   BOOTH,  F.G.S. 

MEMBER    OF    THE    AMERICAN    SOCIETY    OF    CIVIL    ENGINEERS  ;    FORMERLY 

OF     THE     NEW     SOUTH     WALES      GOVERNMENT     RAILWAYS     AND 

TRAMWAYS,      OF     THE     MANCHESTER     STEAM     USERS' 

ASSOCIATION,     OF  THE  BRITISH    ELECTRIC 

TRACTION      COMPANY,     ETC. 


SECOND  EDITION 


NEW   YORK 
E.   P.   BUTTON  AND   COMPANY 

PUBLISHERS 


Printed  in  Great  Britain  ly 
BUTLER  &  TANNER, 
Frame  and  London 


O' 


TABLE  OF  CONTENTS 
PART  I 

THEORY   AND    PRINCIPLES. 

PAGE 

Preface  .         .         .         .          .          .         .         .         •         .13 

INTRODUCTION 

Historical    Notes ;     Advantages    of    Liquid    Fuel ;     Petroleum ; 

General  Notes  ;  Economies  possible  by  the  use  of  Liquid  Fuel       21 

CHAPTER    I 

The  Geology  of  Petroleum  ;  Petroleum  Drilling  ;  Pumping  .       28 

CHAPTER    II 

The  Economy  of  Liquid  Fuel ;  The  Dangers  of  Petroleum  ;  Air 
necessary  for  Combustion  ;  General  Principles  of  Liquid 
Fuel  Combustion  ;  Flame  Analysis  ;  Refractory  Furnace 
Linings  ;  The  Weir  Boiler  ;  Liquid  Fuels  ;  The  necessity  for 
Atomizing  ;  Vapourizing  ;  Varieties  of  Liquid  Fuel ;  Ameri- 
can Petroleum  ;  Russian  Petroleum  ;  Creosote  Oils ;  Tar 
Distillates  ;  Blast  Furnace  and  Shale  Oils  ...  35 

CHAPTER    III 

Texas  Oil ;  Analysis  of  Oil  ;  Physical  Properties  ;  Russian  Oil ; 
Calorific  Capacity  of  Oils  ;  Advantages  of  Liquid  Fuel ;  The 
Use  of  Oil  on  Locomotives  ;  The  World's  Oil  Production  ; 
The  Limits  of  Liquid  Fuel ;  Equivalence  of  Oil  and  Coal ; 
Tests  of  Texas  Oil 48 

CHAPTER    IV 

Chemical  and  other  Properties  of  Petroleum  ;  Water  in  Oil ; 
Petroleums  suitable  for  Fuel;  Physical  Properties  of  Petro- 
leum ;  Specific  Gravity  of  Petroleum ;  Materials ;  Cast 
Iron  ;  Steel ;  Firebricks  ;  Fireclay  ;  Clay  Analysis  ;  Special 
Forms  of  Bricks  ;  Classification  of  Clay  Goods  .  62 

5 

492179 


6  TABLE  OF  CONTENTS 

CHAPTER    V 

PAGE, 

Combustibles  and  Supporters  of  Combustion."  Carbon :  its 
Forms  and  Origin  ;  its  Calorific  Properties  ;  its  Combustion 
and  Chemistry.  Hydrogen  :  its  Physical  and  other  Pro- 
perties ;  its  Compounds  with  Carbon ;  its  Combustion ; 
Air ;  The  Atmosphere  ;  Properties  of  Air.  Oxygen :  its 
Compounds  with  Carbon  ;  its  Properties ;  Water ;  its 
Properties  ;  Origin  and  Sources  of  Water  Impurities  ;  Solu- 
bility of  Salts  ;  Sea  Water  ;  Useful  Data  .  .  .78 

CHAPTER    VI 

Calorific  and  other  Units  ;  Thermo  Chemistry  ;  Heat  ;  Tem- 
perature ;  Thermometers  ;  Specific  Heat  ;  Latent  Heat ; 
Dissociation  ;  Units  of  Heat  ;  Units  of  Work  ;  Units  of 
Weight ;  Gravity  ;  Compound  Units  ;  Calorific  Power  of 
Fuels  ;  Calculation  of  Temperatures  ;  Effects  of  Dissocia- 
tion and  of  Variation  of  Specific  Heat ;  Relative  Volumes 
produced  by  Combustion  ;  Evaporative  Power  of  Fuel ; 
Temperatures  due  to  Combustion  ;  Calculation  of  Calorific 
Capacity  of  Fuels  ;  Smoke  and  Combustion  ;  Varieties  of 
Smoke  ;  Its  Prevention  ;  Influence  of  Refractory  Furnaces  ; 
The  Combustion  of  Bituminous  Fuels ;  Carbon  Vapour ; 
Liquid  Fuels  ;  Furnace  Temperatures  ;  Theoretical  Flame 
Temperature  ;  Total  Heat  generated  ;  Air  Supply  ;  The 
Heat  Properties  of  Carbon  ;  The  Process  of  Coal  Combus- 
tion ;  Effect  of  Vaporizing  Solid  Fuels  ;  Flame  Analysis  ; 
The  Principles  of  Combustion ;  The  Necessity  of  Tem- 
perature ;  Smoke  due  to  Loss  of  Heat  of  Burning  Gases  ; 
The  Use  of  Coloured  Glass  for  Flame  Inspection  ;  The  Weir 
Boiler ;  Ringelmann's  Smoke  Chart  ....  90 


PART    II 

PRACTICE. 

CHAPTER    VII 

Oil  Storage  on  Ships  ;  Example  of  Improvised  Tank  Steamer  ; 
Example  of  Cargo  Steamer ;  Example  of  New  Tank 
Steamer  ;  Use  of  Liquid  Fuel  at  Sea  ;  Supply  of  Oil  at 
Ports  ;  Safety  and  Flash  Point ;  Advantages  for  War  Ships  ; 
Economic  Advantages  of  Liquid  Fuel  .  .  .  .127 

CHAPTER    VIII 

Marine  Furnace  Gear  ;  Arrangement  of  Shell  Line  Steamers ; 
Interchange  of  Coal  and  Oil ;  The  Flannery-Boyd  System ; 
The  Orde  System  ;  Results  of  Use  of  Liquid  Fuel  at  Sea ; 
Wallsend  Slipway  Company's  Arrangement ;  The  Lanca- 
shire Boiler  with  Orde's  System  ;  Korting  System  ;  Howden 
System .133 


TABLE   OF  CONTENTS  7 

CHAPTER    IX 

PAGE 

Liquid  Fuel  Application  to  Locomotives  ;  The  Holden  System ; 
Advantage  of  Oil ;  Method  of  Working  ;  Management  of 
Fire  ;  Particulars  of  Oil  Burning  Locomotive  ;  Regulation 
of  Oil  Supply  ;  The  Atomizer  ;  Life  of  Fire  Boxes  ;  Heating 
the  Oil ;  Air  Heater 154 


CHAPTER    X 

"Application  of  Liquid  Fuel  to  Stationary  and  other  Boilers  ;  The 
Lancashire  Boiler  ;  Cornish  Boiler  ;  Water  Tube  Boiler ; 
Locomotive  Boiler  ;  Level  of  Atomizer  in  Mixed  System ; 
Management  of  Fire  ;  United  States  Navy  Tests ;  The 
Meyer  System  ;  The  Mixed  System  of  Coal  and  Liquid  Fuel 
Combustion  :  its  use  in  the  Italian  Navy ;  M.  Bertin's 
Calculations  .......  .167 


CHAPTER    XI 

Russian  and  American  Locomotive  Practice  ;  The  Baldwin  Com- 
pany's System  ;  The  Equivalence  of  Coal  and  Oil ;  Compari- 
sons of  Cost  of  Liquid  Fuel ;  The  Danger  of  Crude  Oil ;  The 
Urquhart  System  ;  General  Arrangements  ;  Management  of 
Furnace  ;  Firebox  Designs  ;  Smoke  Results  on  Grazi  and 
Tsaritsin  Railway  .  .  .  .  .  .  .  .178 


CHAPTER    XII 

American  Stationary  Practice  with  Liquid  Fuel ;  The  Billow 
System ;  Fuel  Oil  Pumping  Systems ;  Double  Pumping 
Systems  ;  Furnace  Construction  ;  Operating  a  Fuel  Oil  Plant ; 
Examples  of  Boilers  with  Liquid  Fuel  Furnaces  .  .  195 


CHAPTER    XIII 

English  Stationary  Practice  with  Liquid  Fuel ;  The  Kermode 
System  ;  Analysis  of  Borneo  Oil ;  Tests  of  Borneo  Oil ; 
The  Hydroleum  System  ;  Tests  ;  The  Sprayer  ;  Air  Supply  .  208 


CHAPTER    XIV 

The    Combustion   of  Vaporized   Liquids ;    The   Clarkson-Capel 

Burner:  its  Various  Applications;    Starting  Devices  .          .218 


CHAPTER    XV 

Comparison  of  Air  and  Steam  Atomization  ;  The  Ellis  and  Eaves 

System  ;  Steam  Atomization  ;  Air  Atomization  ;  Tests          .      222 


8  TABLE  OP  CONTENTS 

CHAPTER    XVI 

PAGE 

The  Storage  and  Distribution  of  Liquid  Fuel ;  Tanks  ;  Piping  ; 
Ventilation  ;  Great  Eastern  Railway  System  ;  Grazi  and 
Tsaritsin  Railway  System  ;  Oil  Pumps  ;  Flue  Gas  Analysis  ; 
Calculation  of  Volumes ;  The  Orsat  Apparatus  ;  CO2 
Recorders  ;  Calorimetry  and  Draught ;  Calorimetric  Deter- 
minations ;  Draught ;  Gauges ;  Difference  of  Solid  and 
Liquid  Fuel  in  Relation  to  Draught  .  .  .  .228 

CHAPTER    XVII 

Compressed  Air  ;  Air  Compressors  ;  Principles  of  Compression  ; 
Weight  of  Air  necessary  for  Liquid  Fuel  Atomization  ;  Adia- 
batic  Calculation  of  Air ;  Compound  Air  Compression  ; 
Volumetric  Efficiency  ;  Power  to  Compress  Air  ;  Outflow  of 
Air  .  .  242 

CHAPTER    XVIII 

Atomizing  Liquid  Fuels  ;  Various  Atomizers ;  Elementary  Forms  ; 
Vaporizers  ;  The  Symon-House  Burner  ;  Atomizing  Agents  ; 
French  Trials  ;  Air  Compression  ;  Certain  Advantages  of 
Steam  ;  d'Allest  Atomizer  ;  Fvardofski  System  ;  Russian 
Atomizers  ;  Object  of  Atomizing  ;  American  Practice  .  .  250 

CHAPTER    XIX 

Application  of  Liquid  Fuel  to  Metallurgy  ;  The  Hoveler  System     .      266 

CHAPTER    XX 

The  Oil  Engine  ;  The  Diesel  and  other  systems    .          .          •          .270 


PART    III 

Tables  and  Data  .  281 


INDEX  TO  ILLUSTRATIONS 


FIG.  PAGE 

0.  Hypothetical  Section  of  Oil-bearing  Strata        ...        30 

1.  Kiln  Furnace  ........        74 

2.  Form  of  Baffle 74 

3.  Brick  Fire  Arch 75 

4.  Shaped  Bricks 76 

5.  Shaped  Bricks 76 

6.  Unshaped  Arch  Bricks    .          .          .          .          .          .          .76 

7.  Weir  Boiler 121 

8.  Ringelmann  Smoke  Chart 122 

9.  Furnaces,  s.s.  Murex       .......      134 

10.  Furnace  Brickwork,  s.s.  Murex         .          .          .          .          .135 

11.  Furnace,  s.s.  Trocas 136 

12.  Service  Tank,  Flannery-Boyd  System       .          .          .          .137 
13  and  13a.     s.s.  New  York 138 

14.  Water  Tube  Boiler,  Orde's  System  .          .          .  .141 
14a.  Fuel  Bunker,  Draw-off  Pipe 142 

15.  Orde's  Atomizer      ........      144 

16.  Detail  Arrangement  for  Lancashire  Boiler,  Orde's  System    .      145 
17  and  17a.     Design  for  Oil  Furnace,  Wallsend  System  .      146 

18.  Wallsend  Pressure  Burner       .          •          •          •          •          .148 

19.  Diagrammatic  Arrangement,  Wallsend  System  .          .150 
19a.  Detail  Arrangement,  Wallsend  System     .          .          .          .150 

20.  Water  Tube  Boiler,  Wallsend  System       .          .          .          .151 

21.  Furnace,  s.s.  F.  C.  Laeisz       . 152 

22.  Atomizer,  Korting  System       .          .          .          .          .          .153 

22o.  Atomizer,  Korting  System       .          .          .          .          .          .153 

23.  Great  Eastern  Locomotive,  Atomizer,  Holden's  System     .      158 

24.  Atomizer,  Form  (1911),  Holden's  System  .          .          .159 

25.  Atomizer,  Locomotive  Type,  Holden's  System  .          .160 

26.  Great  Eastern  Locomotive,  Holden's  System,  Firedoor     .      161 

27.  American  Locomotive  Firebox  for  Liquid  Fuel          .          .163 

28.  Great  Eastern  Locomotive      .          .          .          .          .          .165 

29.  Lancashire  Boiler,  Holden's  System  .          .          .          .168 

30.  Water  Tube  Boiler  without  Grate,  Holden's  System          .      169 

31.  MacAllan  Variable  Blast  Pipe  Cap  .                              .      170 

32.  Locomotive  Boiler,  Southern  Pacific  R.R.         .          .          .171 

33.  Meyer  System 173 

34.  Atomizer,  Baldwin  System      .          .          .          .          .          .179 

35.  Oil  Regulator,  Baldwin  System 179 

36.  Locomotive  Firebox,  Baldwin  System,  Old       .          .          .180 

37.  Locomotive  Firebox,  Baldwin  System,  New    .          .          .181 


10  INDEX  TO  ILLUSTRATIONS 

FIG.  PAGE 

38.  Goods  Locomotive,  Urquhart  System  .      .          .          .188 

39.  Goods  tender,  Urquhart  System       .          .          .          .          .190 

40.  Firebox,  Urquhart  System       .  .          .          .          .191 

41.  Locomotive  Firebox,  Urquhart  System    .          .          .          .192 

42.  Atomizer,  Urquhart  System    .  193 

43.  Locomotive  Performance  Chart,  Urquhart  System    .          .194 

44.  Atomizer,  Billow  System          .          .  196 

45.  Double  Pumping  System,  Billow      .          .  .      198 

46.  Tuyere,  Billow  System 199 

47.  Tuyere  Block,  Air  Regulator,  etc.,  Billow  System    .          .      200 

48.  Tank  Car  Hose  Connection      ...  .201 

49.  General  Furnace  Mouthpiece  Arrangement,  Billow  System     202 

50.  Underfired  Boiler,  BiUow  System 205 

51.  Water  Tube  Boiler,  Billow  System  .          .          .          .206 
5 la.  General  Arrangement,  Billow  System      ....      207 

52.  Liquid  Fuel  Furnace,  Kermode's  System           .          .          .      209 
52a.  Enlarged  Details,  Kermode's  System        .          .          .          .210 

53.  Furnace  Arrangement,  Kermode's  System         .          .          .211 

54.  Furnace  Arrangement,  Kermode's  System,  Babcock  Boiler     213 

55.  Furnace  Arrangement,  Hydroleum  System        .          .          .215 

56.  Furnace  Arrangement,  Hydroleum  System        .          .          .216 

57.  Clarkson-Capel  Burner  for  Fire  Float       .          .          .          .219 

58.  Clarkson-Capel  Burner  for  Automobile     ....      220 

59.  Air  Heater,  Ellis  and  Eaves  System         ....      223 

60.  Ellis  and  Eaves  Furnace  Door 223 

61.  Oil  Supply  Tank 231 

62.  Weir  Pump    .          .  .                                                  .232 

63.  Diagram  of  Adiabatic  Compression.          ....      244 

64.  Diagram  of  Compound  Compression  with  Intercooling       .      244 

65.  Atomizer,  Hoveler  System       ......      267 

66.  Atomizer,  Rusden-Eeles 251 

67.  Atomizer,  Aerated  Fuel  Process        .....      252 

68.  Atomizer,  Kermode's  Pressure  System     .          .          .          .253 

69.  Atomizer,  Kermode's  Hot-Air  System      ....      254 

70.  Atomizer,  Kermode's  Steam  System          ....      255 

71.  Atomizer,  Hydroleum  System  .....      255 

72.  Atomizer,  Elementary  Form    ......      256 

73.  Atomizer,  Swensson         .          .          .          .          .          .          .256 

74.  Symon-House  Vaporizer  .          .          .          .          .          .257 

75.  Atomizer,  Guyot     ........      258 

76.  Atomizer,  Nozzle  Incorrect  Form    .....      259 

77.  Atomizer,  Nozzle  Correct  Form        .          .          .          .          .259 

78.  Furnace  of  French  Torpedo  Boat  No.  22          ...      260 

79.  Atomizer,  d'Allest 261 

80.  Atomizer,  Double,  d'Allest 262 

81.  Atomizer,  Soliani   .          .          .          .  .          .          .     263 

82.  Torpedo  Boiler  tried  at  Cherbourg  ....      264 
82a.  Assembly  of  Gregory's  Fuel  Oil  Burner  ....   265s 

83.  Hornsby-Akroyd  Engine           .          .  .          •          .272 

84.  Cross  Section,  Vaporizer,  Hornsby-Akroyd        .          •          .273 

85.  Griffin  Engine  Vaporizer  .          .          •          •          -          .276 


INDEX  TO  TABLES 


TABLE  PAGE 

I     Composition  of  Crude  Oils 281 

II  Calorific  Capacity  of  Liquid  Fuel  Oils      .          .          .281 

III  Coefficient  of  Expansion  of  Crude  Oil  .          .281 

IV  Calorific  Capacity  of  Crude  Oil         ....      284 
V  Table  of  the  Properties  of  Gases  (Kempe)        .          .     282 

VI     Temperature  Table 284 

VII     Specific  Heat  of  Gases 284 

VIII     Equivalents,  Various 285 

IX  Calorific  Properties  of  Carbon            ....      285 

X  Tension  of  Aqueous  Vapour    .          .          .          .          .286 

XI  Relative  Economy  Oil  and  Coal      ....      286 

XII  Russian  and  Pennsylvanian  Oils,  Analysis  of   .          .      286 

XIII  Comparative  Trials  of  Petroleum  Refuse  .          .287 

XIV  Conversion  Table,  Degrees  Baume  ....      288 
XV  Heat  of  Combustion  (B.  Th.  U.)  und  Air  per  Pound 

of  Fuel      .          . 288 

XVI  Theoretical  Flame  Temperatures       .          .          .          .289 

XVII  Weight  and  Volume  of  Gases            .          .          .          .289 

XVIII  Weight  and  Volume  of  Oxygen  and  Air  for  Combustion. 

Metric 290 

XIX  Weight  and  Volume  of  Oxygen  and  Air  for  Combustion. 

English 290 

XX  Theoretical  Evaporative  Value  of  Petroleum  and  Coal     291 

XXI  Ignition  Temperature  of  Gases         ....     292 

XXII  Conversion  Tables  for  Evaporation  and  Combustion       292 

XXIII  Temperature  Determination  by  Fusion  of  Metals      .      293 

XXIV  Volume  and  Weight  of  Dry  Air       .  .293 
XXV  B.  Th.  U.  in  Water         .    *      ,          .                              .294 

XXVI  Saturated  Steam  Data    ...                              .     294 

XXVII  Factors  of  Evaporation  ...                              .295 

XXVIII  Heat  Balance  Table         ...                              .     296 

XXIX  Heat  Lost  in  Chimney  Gases  (Diagram)                     -     297 


PREFACE  TO  LARGER  EDITION 
OF  1903 


subject  of  Liquid  Fuel  is  one  that  has  now  been  before 
X  the  public  about  twenty-five  years,  but  little  had  been 
done  in  this  country  until  about  twelve  years  ago,  when  Mr. 
Holden,  of  the  Great  Eastern  Railway,  began  to  use  the  tar 
of  his  oil-gas  process,  and  found  many  advantages  in  using 
this  hitherto  almost  unsaleable  product.  The  success  of  this 
tar  led  him  on  to  the  use  of  creosote  and  other  hydrocarbon 
by-products,  and  now  he  is  using  Texas  oil. 

In  this  book  the  Author  has  endeavoured  to  put  together 
what  has  been  done  in  the  burning  of  liquid  fuel,  and  at  the 
risk  of  repetition  has  given  descriptions  of  various  systems  and 
apparatus  ;  and  while  no  statements  have  been  accepted 
unconsidered,  he  has  not  hesitated  to  use  descriptions  and 
statements  of  manufacturers  in  some  cases  with  little  altera- 
tion where  such  statements  were  sound  and  reasonable.  The 
Author  is  not  only  indebted  to  the  many  whose  names  appear 
in  the  text,  but  also  to  many  others  who  have  furnished  him 
with  information,  particularly  Professor  W.  B.  Phillips,  Ph.D., 
of  the  University  of  Texas,  from  whose  bulletins  the  Author 
has  drawn  so  copiously  for  information  on  Texas  oil  ;  to  Mr. 
Thomas  Urquhart,  of  Dalny,  who,  as  Locomotive  Superin- 
tendent of  the  Grazi  and  Tsaritsin  Railway,  first  placed  liquid 
fuel  burning  on  a  sound  basis  in  locomotive  work,  and  whose 
papers  on  the  subject  may  be  found  in  the  Proceedings  of 
the  Institution  of  Mechanical  Engineers  ;  to  his  friend  Mr. 
B.  H.  Thwaite,  whose  researches  in  combustion  have  been  so 
extensive. 

The  work  of  the  United  States  Naval  Department,  under 
Rear-Admiral  Melville,  has  been  so  valuable  that  special 
appendices  have  been  devoted  to  a  copious  abstract  of  the 
coal  and  oil  tests  made  by  the  Bureau  of  Steam  Engineering 
upon  a  water-tube  boiler  as  well  as  tests  upon  the  s.s.Mariposa 

The  Author  has  also  drawn  liberally  upon  the  bulletins  of 
the  U.S.  Geological  Survey  for  information  on  petroleum 
production. 

13 


14       PREFACE  TO  LARGER  EDITION   OF   1903 

To  Mr.  Alfred  J.  Allen  acknowledgment  is  due  for  informa- 
tion on  tar  and  creosote,  and  for  tabular  matter  to  Mr.  Poole, 
whose  excellent  treatise  on  the  Calorific  Power  of  Fuels  deals 
so  exhaustively  with  coal. 

Appendices  are  added  giving  the  Rules  of  the  National 
Board  of  Fire  Underwriters  (U.S.),  and  also  the  Rules  of 
Lloyd's  Register  of  Shipping. 

Acknowledgments  are  due  to  the  Electrical  Review  (London) 
for  permission  to  reproduce  portions  of  the  Author's  articles 
in  that  Journal  on  questions  of  combustion.  To  Mons.  L. 
Bertin,  of  the  French  Navy,  the  Author  is  indebted  for  infor- 
mation as  to  the  use  of  liquid  fuel  in  the  French  Military  Marine. 

The  means  for  utilizing  Liquid  Fuel  are  very  varied,  yet 
all  practically  result  in,  or  at  least  aim  at,  one  end.  It  has 
been  impossible  within  two  covers  to  do  more  than  select  a 
number  of  such  apparatus  to  illustrate  the  principles  which 
have  been  followed  in  achieving  success.  The  successful  com- 
bustion of  liquid  hydrocarbon  is  but  an  extension  of  the  prin- 
ciples necessary  for  bituminous  or  hydrocarbon  coal.  The 
difference  is  that  coal  is  burned  partly  upon  the  grate,  and  air, 
to  burn  the  hydrocarbon  distillates,  cannot  well  be  introduced 
from  below,  as  it  can  with  liquid  fuel  which  is  burned  in  a 
floating  condition,  and  can  be  fed  with  air  from  below  very 
easily. 

The  difference  is  but  one  of  degree,  but  with  liquid  fuel  the 
fact  that  all  the  fuel  is  floating,  and  would  produce  a  specially 
foul  black  smoke  under  the  conditions  in  which  coal  is  burned, 
has  compelled  the  adoption  of  means  that  ought  to  be  adopted 
with  coal-fired  furnaces. 

The  Author  has  endeavoured  to  connect  the  two  practices, 
for  in  the  present  state  of  liquid  fuel  supply  it  is  more  than 
probable  that  its  use  will  be  parallel  with  the  use  of  coal, 
especially  hi  dealing  with  the  sudden  and  high  load  peaks  of 
electric  stations.  Liquid  fuel  cannot  be  universal  unless  the 
supply  increases  to  many  times  what  it  is  at  present,  and 
this  points  to  a  good  future  for  the  mixed  system  of  firing, 
oil  and  coal  being  burned  together  in  the  same  furnace. 

It  has  been  difficult  to  make  a  selection  of  apparatus  to  be 
described,  but  the  Author  trusts  that  he  has  selected  a  suffi- 
cient number  of  types  practically  to  cover  the  ground  and 
show  the  general  trend  of  practice  without  unduly  multiplying 
examples.  Indeed  the  tendency  seems  to  him  to  be  in  the 
direction  of  one  general  type.  As  regards  special  boilers,  oil 
does  not  appear  to  require  anything  more  than  what  is  re- 
quired by  coal,  though  coal  is  not  treated  to  the  necessary 


PREFACE  TO  LARGER  EDITION   OF    1903        15 

appliances,  and  oil  is  so  treated,  and  gains  success  where  coal 
is  allowed  to  fail. 

Much  that  perhaps  ought  to  appear  in  such  a  book  as  this 
has  been  omitted,  as  it  appears  to  the  Author  that  the  question 
of  draught,  for  example,  is  not  of  the  same  importance  with 
liquid  fuel  as  it  is  with  solid  fuels. 

More  might  be  said  on  the  subject  of  flue-gas  proportion,  but 
this  again  has  been  so  fully  treated  by  other  writers  that  it 
did  not  seem  desirable  at  present  to  deal  with  it  more  fully. 
The  most  important  detail  of  liquid  fuel  apparatus  is  the  fur- 
nace and  the  provision  of  air,  and  of  means  to  secure  combus- 
tion and  conserve  temperature  to  enable  combustion  to  be 
made  perfect. 

Mr.  Horace  Allen  kindly  revised  the  section  on  gas  analysis. 
Students  of  liquid  fuel  combustion  will  find  enormous  masses 
of  information  in  the  past  volumes  of  the  Engineer,  Engineer- 
ing, and  other  technical  papers.  Much  of  this  information 
is  duplicated  and  historical,  and  the  Author  has  found  it 
necessary  to  eliminate  almost  all  such  matter  and  confine  his 
space  to  systems  now  living  or  of  recent  use,  or  of  a  form  recog- 
nized as  useful  to-day.  Undoubtedly  Aydon  and  the  late 
Admiral  Selwyn  did  much  to  urge  the  use  of  liquid  fuel,  but 
the  latter  injured  the  value  of  his  best  work  by  regarding 
steam  as  a  combustible. 

The  Author  is  also  indebted  to  Messrs.  Colonner  and  Lordier, 
the  French  engineers,  for  excellent  information  on  liquid 
fuel,  and  indirectly  no  doubt  to  many  others  who  are  not 
directly  traceable. 

Finally,  his  grateful  acknowledgments  are  due  to  his  Pub- 
lishers for  the  manner  in  which  they  have  facilitated  his  labours 
throughout. 

WESTMINSTER. 


PREFACE 

THE  object  of  this  book  is  to  present  in  a  handy  form  the 
more  immediate  practical  points  of  the  Author's  larger 
work  on  the  same  subject.1 

In  that  book  the  Author  endeavoured  to  present  not  merely 
the  subject  of  liquid  fuel  combustion  but  such  side  issues  as 
water  softening,  and  considerably  more  on  the  general  theory 
of  combustion  and  the  physical  properties  of  materials  than 
can  be  found  room  for  in  this  present  work. 

The  larger  work  is  still  available  for  those  who  may  desire 
the  fuller  presentation  of  the  subject,  but  it  was  written  at  a 
time  when  the  popular  idea  of  liquid  fuel  was  very  hazy,  and 
when  the  world's  production  of  petroleum  was  very  much  less 
than  it  is  to-day.  The  ideas  then  presented  by  the  Author 
have  since  received  very  general  acceptance.  Over  parts  of 
the  world  liquid  fuel  will  continue  to  take  the  place  of  coal. 
In  other  parts  it  will  be  used  because  by  its  means  things  may 
be  accomplished  that  would  not  be  possible  with  coal.  This 
was  amply  demonstrated  during  the  naval  manoeuvres  a  year 
or  two  ago,  when  the  stokehold  crew  of  one  of  the  rival  fleet 
divisions  were  worn  out  and  unfit  for  further  effort.  Liquid 
fuel  was  then  resorted  to  and  the  ships  simply  ran  away  from 
the  "  enemy  "  and  ravaged  the  south  coast. 

Much  of  what  appears  in  the  larger  work  is  eliminated 
because  of  the  foregoing  reasons  as  well  as  the  fact  that  the 
subject  of  liquid  fuel  is  now  quite  removed  from  controversy 
and  has  entered  more  fully  upon  the  commercial  stage,  for 
liquid  fuel  will  now  be  used  wherever  it  is  cheaper  than  coal 
or  possesses  circumstantial  advantages  which  outweigh  expense. 
For  the  peak  loads  of  electric  light  supply  undertakings  liquid 
fuel  presents  itself  so  favourably  that  only  surprise  can  be  felt 
that  this  particular  field  has  so  far  been  neglected. 

This  book  will  therefore  be  fairly  closely  confined  to  the 
use  of  liquid  fuel  in  steam  raising  and  in  direct  power  produc- 
tion in  the  internal  combustion  engine.  This  engine  has  in 
the  last  few  years  made  great  advances  and  bids  fair  soon  to 

1  Liquid  Fuel  and  Its  Combustion.     Constable  &  Co.,  1902. 

17  B 


18  PREFACE 

find  itself  employed  as  the  motive  power  producer  in  ships  of 
great  size  and  tonnage. 

While  bringing  up  to  date  the  examples  of  apparatus  these 
have  been  reduced  in  number.  Tabular  matter  has  been 
abridged  in  numbers  and  detail  and  much  experimental  record 
has  had  to  be  cut  out  in  order  to  bring  the  book  within  its 
intended  compass. 

Finally  it  may  be  added  that  since  the  issue  of  the  Author's 
larger  book,  there  has  been  little  change  in  the  methods  or 
apparatus  employed,  though  there  is  a  steady  extension, 
chiefly  abroad,  in  the  uses  to  which  liquid  fuel  has  been  put. 

The  Author  trusts  he  has  given  sufficient  examples  of 
apparatus  to  enable  any  engineer  to  adapt  liquid  fuel  to  his 
own  conditions.  He  wishes  to  make  it  clear  that  the  examples 
and  illustrations  are  chosen  as  examples  and  are  not  put 
forward  as  being  other  than  typical.  It  is  not  possible  to 
make  a  book  into  a  complete  catalogue  of  apparatus,  and 
only  a  few  can  be  selected  as  types. 

WM.  H.  BOOTH. 

38,  BROAD  STREET  AVENUE,  E.G. 
Oct.,  1911. 


There  is  still  a  big  field  for  the  use  of  systems  of  mixed 
solid  and  liquid  fuel,  as  carried  out  notably  with  the  Gregory 
burner  described  in  Chapter  XVIII.  (June,  1921.) 


Part    I 
THEORY  AND   PRINCIPLES 


INTRODUCTION 

THE  first  really  practical  and  efficient  employment  of 
liquid  fuel  for  steam-raising  purposes  appears  to  be 
due  to  Mr.  Thomas  Urquhart,  of  the  Grazi  and  Tsaritzin  Rail- 
way of  Russia.  Mr.  Urquhart  used  the  spraying  system  and 
obtained  good  results,  and  his  paper  of  1884 1  marks  the 
beginning  of  the  period  of  really  useful  work. 

The  application  of  liquid  fuel  in  the  Caucasus  owes  its  success 
to  a  combination  of  causes.  Russian  petroleum  has  less  light 
oil  in  its  composition,  and  therefore  produces  more  astatki, 
i.e.  mazut  or  residuum  ;  coal  is  dear  in  the  district,  and  the 
man  was  present  in  Mr.  Urquhart  to  render  the  application  of 
liquid  fuel  successful,  previous  applications  not  having  proved 
so. 

Urquhart  placed  the  use  of  liquid  fuel  on  a  sound  basis. 

The  Chicago  Exhibition  in  the  early  nineties  gave  great 
impetus  to  the  use  of  liquid  fuel  in  America,  for  all  the  boilers 
there  were  arranged  with  oil  fuel  only. 

In  Great  Britain  the  use  of  liquid  fuel  has  not  been  extensive, 
but  it  has  been  marked  by  good  practice,  and  only  bids  fair 
to  become  extensive  since  the  introduction  of  mineral  oil. 
Previously  the  tendency  had  been  to  use  the  products  of  distil- 
lation of  coal  or  oil  in  the  shape  of  tars  or  creosotes. 

To-day  liquid  fuel  is  well  established  and  recognized  as  a  fuel 
of  extreme  elasticity,  and  one  that  can  be  burned  smokelessly. 
The  days  of  experiment  are  past,  and  no  serious  difficulties 
remain  to  be  overcome.  Since  1902  liquid  fuel  has  been 
adopted  in  the  British  Navy,  and  it  is  understood  that  very 
satisfactory  results  have  been  secured. 

At  the  same  time  the  question  must  be  considered  from  a 
conservative  standpoint,  because  for  years  to  come,  if  ever,  the 
output  of  petroleum  will  not  be  sufficient  to  make  it  a  serious 
rival  of  coal  in  every  use.  There  is  no  certainty  of  extensive 
petroleum  production  in  the  future.  Petroleum  wells  do  not 
endure  indefinitely.  They  are  not  like  water  wells,  fed  from 

1  Institution  of  Mechanical  Engineers,  Minutes  of  Proceedings,  1884. 

21 


22  LIQUID  FUEL  AND  ITS   APPARATUS 

surface  rainfall,  and  geology  does  not  assure  us  that  they  are 
being  fed  from  still  deeper  sources,  nor  is  it  decided  whether 
petroleum  is  of  mineral  or  of  organic  origin.  The  future  of 
petroleum  is  thus  uncertain. 

GENERAL  CONSIDERATIONS 

A  general  idea  of  the  liquid  fuel  problem  should  therefore 
be  obtained  before  attempting  to  gauge  its  merits. 

There  is  a  lack  of  the  sense  of  proportion  in  many  who 
discuss  the  question  of  liquid  fuel. 

In  Great  Britain  alone  over  250  million  tons  of  coal  are 
raised  each  year.  In  the  United  States  the  amount  is  still 
greater.  The  present  production  of  mineral  oil  is  a  mere 
fraction  of  the  millions  of  tons  of  coal  produced  in  the  world. 

Liquid  fuel  has  undoubted  advantages  in  many  cases,  and 
probably  nowhere  could  it  be  used  to  better  advantage  than 
in  an  electric  light  station. 

One  of  the  principal  advantages  of  oil  is  its  high  calorific 
value  per  pound.  This,  with  the  best  oils,  is  double  the 
capacity  of  the  inferior  coals,  and  30  per  cent,  better  than  the 
best  coal.  The  ease  with  which  it  can  be  stored  and  moved 
from  point  to  point  is  an  advantage.  It  can  be  fired  mechani- 
cally, makes  no  ash  or  clinker,  can  be  burned  at  maximum  rate 
or  entirely  turned  off  in  a  moment.  Further,  a  very  large 
power  of  boilers  requires  very  little  labour  in  the  stokehold. 
Petroleum  consists  of  a  very  large  variety  of  constituents, 
gaseous,  liquid,  or  solid.  The  gas  is  marsh  gas,  CH4,  and  at 
once  disappears  ;  the  lighter  liquids  are  very  volatile,  and 
finally  there  are  solid  bodies  at  the  end  of  a  long  series  of 
liquids  of  varying  degrees  of  volatility  and  specific  gravity. 

The  chemical  formulae  which  cover  most  of  the  constituents 
of  petroleum  are  CnH2n  and  CnH2n±2.  These  formulae  con- 
tinue throughout  the  whole  range  from  marsh  gas,  CH4, 
onwards. 

Texas  oil  is  used  chiefly  as  it  is  found. 

Russian  oil  is  used  in  the  form  of  astatki,  the  residuum  after 
distilling  off  the  lighting  and  lubricating  oils.  Much  of  the 
American  oil  is  also  used  in  the  form  of  residuum. 

The  proportion  of  carbon  in  all  the  liquids  used  as  fuel  varies 
very  little  from  84  per  cent.,  the  hydrogen  amounting  to  16 
per  cent.  There  is  little  else,  so  that  petroleum  is  practically 
all  combustible. 

It  is  well  established  that  there  is  at  present  only  one  way 
to  burn  liquid  fuel  for  steam  raising,  and  that  is  by  atomizing 
the  fuel  in  company  with  &  sufficient  amount  of  air  around 


INTRODUCTION  23 

each  atom.  In  order  that  oil  may  atomize  freely,  it  should  be 
deprived  of  viscidity  by  heat.  Heat  also  causes  any  water 
in  the  oil  more  easily  to  separate  out,  first,  because  heated  oil, 
being  more  limpid  offers  less  resistance  to  the  freeing  of  the 
water  ;  and  secondly,  there  is  greater  expansion  of  oil  than  of 
water  due  to  the  heat,  and  the  water  gains  a  relatively  greater 
specific  gravity. 

Warming  is  done  by  a  steam  coil,  and  may  be  merely  local 
warming  in  the  vicinity  of  the  take-off  valve  in  the  tank.  It 
is  essential  that  water  be  fairly  well  separated,  because  if  it 
comes  through  the  burners  in  any  quantity  it  may  extinguish 
the  fires,  and  the  next  following  oil  is  apt  lo  ignite  explosively. 

In  storing  oil  there  is  always  apt  to  be  some  vapour  given  off, 
and  an  empty  tank  ought  not  to  be  entered  with  a  light. 

Though  not  nominally  of  double  the  calorific  capacity  of 
average  fair  coal,  oil  is  found  in  practice  to  be  worth  double  the 
price  of  coal,  owing  to  the  labour  cost  which  it  saves. 

This  is  as  regards  marine  service,  for  the  oil  can  be  carried  in 
ballast  tanks,  and  paying  cargo  is  carried  in  the  coal  bunker 
space. 

For  land  purposes,  these  latter  considerations  do  not  weigh, 
and  the  relative  values  must  be  based  on  the  performance 
ratio  of  about  16  to  10,  together  with  the  economy  of  labour, 
cleaning,  ash  cartage,  etc. 

Above  and  beyond  all  these  things,  however,  is  the  power 
which  liquid  fuel  gives  of  immensely  increasing  the  steam- 
production  of  a  boiler  at  short  notice. 

In  general  practice  a  steam-boiler  is  designed  with  a  given 
ratio  of  heating  surface  per  unit  of  fuel  burned.  Any  reduction 
of  this  ratio  is  accompanied  by  a  poorer  performance.  Less 
steam  is  produced  per  pound  of  oil  consumed.  A  reduction  of 
the  heating  surface  ratio  does  not,  however,  reduce  the  per- 
formance by  anything  like  the  same  ratio. 

If  a  large  demand  for  steam  is  made  upon  a  boiler  for  a  short 
fraction  of  its  working  hours,  it  may  be  cheaper  to  consume 
fuel  at  a  high  rate  for  a  fraction  of  the  time  than  to  employ 
two  or  even  three  boilers  at  normal  rates  during  a  fraction  of 
the  day,  the  extra  boilers  remaining  idle  during  the  rest  of  the 
day  ;  albeit  when  the  heavy  load  is  past  these  extra  boilers 
are  retired  hot  and  full  of  energy.  The  saving  by  the  first 
method  is  very  considerable  in  respect  of  space  occupied,  build- 
ings and  capital  cost  generally,  and  if  not  carried  too  far  it 
will  outweigh  the  fuel  cost  of  the  short  run  at  heavy  output. 

For  this  system  of  working,  coal  can,  of  course,  be  employed. 
Coal,  however,  cannot  be  fired  at  abnormal  rates  with  special 


24  LIQUID  FUEL  AND  ITS  APPARATUS 

ease.  A  mechanical  stoker  does  not  readily  increase  its  rate 
of  working.  The  better  forms  of  stoker — on  the  coking  prin- 
ciple— cannot  put  their  whole  grate  surface  into  the  new  and 
forced  condition.  The  sprinkler  class,  again,  do  not  work 
well  at  abnormal  rates.  Coal  combustion  is  only  to  be  regu- 
lated by  draught  intensity.  With  oil,  the  supply  is  instantly 
variable  to  suit  the  steam  required,  and  a  boiler  can  rapidly 
give  its  fullest  output.  With  boilers  of  the  smaller  tube  type 
especially,  their  small  water  contents  enables  the  engineer  to 
leave  them  standing  cold  to  within  a  short  time  of  maximum 
output.  Oil  is  then  turned  on,  and  in  a  few  minutes  the  boiler 
is  in  full  work.  When  a  boiler  is  already  at  work  the  mere 
turn  of  a  handle  puts  it  into  its  maximum  steam-producing 
condition. 

So  soon  as  the  demand  ceases  the  oil  can  be  turned  off,  and 
the  normal  coal  fire  continued,  or  the  boiler  laid  off  entirely. 
By  means  of  liquid  fuel  great  elasticity  is  possible. 

In  a  lighting  station  the  load  factor  is  very  usually  about  12 
per  cent.  That  is  to  say,  about  one-eighth  of  the  plant  is,  on 
the  average,  at  work  all  the  working  hours. 

This  excessive  misproportion  is  remedied  to  any  desired  extent 
by  means  of  accumulators,  but  it  is  not  yet  commercially 
economical  to  instal  so  high  a  proportion  of  battery  power  as 
to  enable  the  power-plant  to  run  at  steady  load  all  day.  The 
peak  of  the  load,  however  short  in  duration,  cannot  be  sur- 
mounted without  the  aid  of  power,  and  it  is  to  the  height  and 
small  duration  of  the  maximum  load  curve  that  the  poor  load 
factor  of  a  lighting  station  is  due.  Accumulators  for  heavy 
output  of  short  duration  greatly  improve  the  load  factor,  but, 
in  any  case,  the  number  of  boilers  at  work  to  tide  over  the  peak 
is  several  times  the  mean  number. 

If,  by  means  of  liquid  fuel,  boilers  can  be  heavily  pushed 
for  two.  three,  or  four  hours,  the  capital  outlay  on  boilers  will 
be  much  reduced.  When  the  various  points  are  taken  into 
account,  the  boiler  scheme  that  will  probably  suggest  itself 
will  be,  first,  some  boilers  of  the  Lancashire  type,  economical 
and  steady  steamers  ;  secondly,  large  tube  boilers  with  a 
moderate  water  contents  and  large  grate  area,  and  with  efficient 
steam  driers  or  superheaters.  These  boilers  can  be  heavily 
forced  with  some  sacrifice  of  economy,  but  the  priming  due  to 
heavy  forcing  must  be  eliminated  by  a  good  superheater.  This 
is  essential  to  economy.  Thirdly,  small  tube  boilers  of  very 
small  water  capacity,  capable  of  being  heavily  forced,  delivering 
their  steam  preferably  above  water  level  in  the  steam  drum. 
If  all  these  boilers  are  fitted  with  oil  sprayers,  the  maximum 


INTRODUCTION  26 

demand  for  steam  will  be  met  with  the  minimum  of  capital 
outlay. 

It  is  a  fallacy  to  suppose  that  boilers  of  small  water  capacity 
respond  most  readily  to  a  sudden  demand  for  steam. 

When  a  boiler  is  at  work  under  full  pressure,  the  whole  of  its 
water  is  at  a  temperature  which  corresponds  with  the  pressure. 
Any  addition  to  the  furnace  activity  cannot  add  to  the  hea'o 
contents  of  the  boiler,  unless  the  pressure  is  allowed  to  rise  ; 
obviously,  therefrom,  given  the  continuance  of  the  same  pres- 
sure, the  boilers  of  large  water  contents  will  answer  to  an  urged 
fire  just  as  rapidly  as  a  boiler  of  small  water  contents.  When 
boilers  are  standing  at  rest,  however,  and  cold,  the  boiler  which 
contains  the  least  water  will,  ceteris  paribus,  become  most 
quickly  hot.  Such  a  boiler  as  the  Solignac,  which  holds  almost 
no  water,  can  be  made,  by  aid  of  oil  fuel,  to  produce  its  maxi- 
mum power  in  a  few  minutes  after  lighting  up. 

In  this  respect  oil  has  a  decided  advantage  over  solid  fuel. 
To  secure  a  good  fire  with  solid  fuel  there  must  be  a  thick  bed 
of  incandescent  fuel  on  the  grate,  and  this  can  only  be  built 
up  with  comparative  slowness,  and  when  its  duty  is  over  it 
remains  a  more  or  less  wasted  force.  With  oil,  however,  the 
maximum  fire  is  instantaneous,  and  the  only  drawback  is  the 
cold  brickwork  of  the  setting,  which  must  become  hot  before 
the  maximum  furnace  duty  is  attained. 

For  ordinary  economical  work  the  number  of  heat  units  that 
a  boiler  can  absorb  per  square  foot  of  heating  surface  will  not 
be  changed  when  liquid  fuel  is  employed,  except  so  far  as  liquid 
fuel  can  be  burned  without  smoke  more  easily  than  can  solid 
hydrocarbons,  such  as  coal,  and  thereby  the  heating  surface 
is  maintained  clean  and  free  from  dust  and  soot,  and  more 
efficient.  Evaporative  efficiency  must  not  be  allowed  to  out- 
weigh the  overall,  or  commercial,  efficiency.  Exactly  what 
governs  the  relation  between  evaporative  and  commercial 
efficiency  cannot  be  stated  positively.  Indeed,  commercial 
efficiency  alone  should  be  considered  as  the  true  basis  of  design. 
It  may,  however,  be  stated  in  general  terms  that  plant  which 
is  on  duty  for  long  hours  may  be  designed  to  work  more  economi- 
cally as  regards  fuel  than  plant  intended  to  work  very  short 
hours. 

Let  it  be  assumed  that  the  boilers  which  are  economical  of 
fuel  have  an  efficiency  of  72  per  cent.,  and  that  the  small  highly 
pushed  boilers  are  run  at  60  per  cent,  efficiency  for  three  hours. 

Then,  in  course  of  a  year,  fuel  is  wasted  which  represents  12 
per  cent,  difference  of  efficiency  lost  for  three  hours  daily. 
To  enable  this  loss  to  be  avoided  there  would  be  so  many 


26  LIQUID  FUEL  AND  ITS  APPARATUS 

thousands  of  pounds  extra  capital  cost  in  boilers,  buildings, 
etc.,  and  where  oil  is  not  employed,  so  much  more  labour  cost 
as  compared  with  oil.  Properly  equated  at  a  suitable  rate  of 
interest  and  depreciation,  the  relative  value  of  the  alternative 
systems  may  be  found  after  the  manner  of  the  Kelvin  law 
applied  to  cable  work.  In  many  stations  the  extra  labour 
for  the  heavy  duty  period  is  difficult  to  arrange  satisfactorily. 
Men  are  employed  more  hours  than  they  really  work,  and  where 
it  may  be  best  to  use  coal  for  10  hours,  the  labour  cost  may 
make  it  cheaper  to  use  oil  for  4  hours  of  a  peak  load,  even  if, 
in  mere  fuel  cost  per  unit,  the  oil  is  more  expensive. 

Trials  with  liquid  fuel  show  that  there  is  still  much  to  be 
done  in  reducing  the  air  supply.  The  air  required  to  burn  1 
unit  weight  of  carbon  is  11 J  units.  An  ordinary  oil  fuel  re- 
quires fully  15  units,  with,  of  course,  some  additional  excess 
as  with  solid  fuel.  But  with  oil  fuel  there  ought  to  be  better 
mixture  of  air  and  fuel,  and  therefore  better  combustion  with 
less  excess  of  air. 

If  we  regard  air  as  the  fuel  and  coal  or  oil  as  the  sustainer  of 
combustion,  as  we  have  a  chemical  right  to  do,  we  shall  arrive  at 
the  conclusion  that,  approximately,  the  calorific  value  of  a  fuel 
in  actual  duty  done  will  not  differ  much  from  the  chemical 
ratio  of  air  required  in  the  combustion  process.  The  large 
amount  of  air  per  pound  of  oil  arises  from  the  large  percentage 
of  hydrogen  in  the  oil,  and  it  is  the  large  capacity  for  oxygen 
possessed  by  hydrogen  which  renders  the  theoretical  tem- 
perature of  combustion  so  nearly  like  that  of  carbon,  in  spite 
of  the  high  calorific  capacity  of  hydrogen. 

As  regards  the  production  of  petroleum,  that  of  the  United 
States  in  the  year  1901  was  69,389,194  barrels,  valued  at  66 J 
million  dollars.  If  each  barrel  is  assumed  to  contain  360  lb., 
or  say  6  barrels  per  ton,  the  total  tonnage  will  be  11,565,000, 
and  the  value,  therefore,  something  under  23<s.  per  ton,  or  prac- 
tically $1  per  barrel.  Thus  the  weight  of  oil  produced  in  the 
United  States  was  about  5  per  cent,  of  the  weight  of  coal,  or 
say  7J  per  cent,  of  the  calorific  capacity.  After  the  removal 
of  the  lighting  and  lubricating  oils,  the  amount  of  fuel  oil 
remaining  was  quite  small  as  compared  with  the  coal  output. 
It  may  be  assumed  that  the  total  oil  production  of  the  world 
is  not  5  per  cent.1  of  its  coal  production.  Any  idea  of 
entirely  displacing  the  coal  must  be  out  of  the  question,  unless 
the  yield  of  oil  be  increased  beyond  present  prospects,  and  the 
use  of  fuel  must  therefore  be  undertaken  with  common-sense 

1  1921.     The  ratio  is  now  about  10  per  cent. 


INTRODUCTION  27 

caution,  and  not  in  any  wholesale  manner,  to  the  expected 
exclusion  of  coal. 

At  the  same  time,  when  the  limitations  of  the  subject  are 
recognized,  it  cannot  be  denied  that  liquid  fuel  lends  itself  to 
certain  conditions  as  to  steam  raising  which  must  render  it 
extremely  valuable  and  of  great  convenience.  Marine  work 
and  electrical  work  are,  par  excellence,  the  two  lines  along 
which  liquid  fuel  appears  likely  to  advance  most  successfully, 
and  in  the  author's  opinion  steam-driven  motor  cars  may 
eventually  discard  the  dearer  oils  and  employ  the  heavy  oils 
and  residuum  as  fuel  by  means  of  atomizers.  According  to 
present  appearances,  the  motor  car  or  tractor  offers  one  of  the 
finest  fields  for  the  use  of  the  heavy  fuel  oils,  as  distinguished 
from  the  petrols  or  even  the  cheap  lamp  oils,  such  as  are  already 
used  on  steam  cars.  Little  has  yet  been  done  in  this  direction. 
It  may,  however,  be  added  that  the  commoner  grades  of  para- 
ffine  are  at  present  so  cheap  that  such  vehicles  as  steam  omni- 
buses are  not  tempted  to  depart  from  paraffine  in  favour  of 
heavier  oils.  Such  cheapness  appears  to  arise  from  fighting 
competition,  and  if  so  will  not  last. 

1921.  Much  was  done  quietly  during  the  war  by  way  of 
introducing  liquid  fuel  throughout  the  Navy.  The  pressure- 
jet  system  of  atomization  by  high  pressure  came  well  to  the 
front.  This  atomization  through  small  whirl  passages  of 
course  demands  good  heating  and  filtration  and  it  is  about 
10  per  cent,  superior  in  economy  to  air  or  steam  systems. 

As  an  example  of  what  oil  will  do  may  be  cited  the  case 
of  a  6,000  i.h.p.  destroyer  of  30  knots  and  350  tons,  which 
burned  139  pounds  of  coal  per  100  ton-miles,  whereas  a  later 
34-knot  boat  of  800  tons  and  nearly  18,000  i.h.p.  burned  only 
83  pounds  of  oil  per  100-ton  miles.  More  duty  per  ton-mile 
is  of  course  to  be  expected  in  a  bigger  vessel,  but  the  com- 
parison is  notable.  In  the  U.S.  Navy  oil  and  coal  have  been 
found  to  have  a  relative  evaporation  of  1445  and  9-31. 


CHAPTER    I 

THE    GEOLOGY    OF   PETROLEUM 

IN  this  book  very  short  reference  only  is  needed  to  the  sub- 
ject of  the  Geology  of  Petroleum  and  the  method  of 
procuring  it. 

Petroleum  is  found  in  various  geological  formations,  from 
the  Silurian  and  Carboniferous  in  the  United  States,  to  the 
Tertiaries  in  the  eastern  hemisphere.  It  indicates  its  presence 
sometimes  by  the  escape  of  inflammable  gas  at  the  surface, 
sometimes  by  the  existence  of  deposits  of  pitch  or  asphaltum, 
as  at  La  Brea  in  Trinidad,  where  a  large  lake  of  pitch  has  been 
recently  proved  to  have  indicated  petroleum  below.  Some- 
times petroleum  oozes  from  surface  outcrops.  Where  there 
are  no  surface  indications  petroleum  may  be  inferred  to  exist 
where  the  geological  conditions  resemble  those  of  known  and 
proved  fields.  But  no  geological  knowledge  can  go  beyond 
this.  In  a  proved  field  there  is  greater  certainty  of  success 
along  any  particular  line  of  country  with  each  successful  boring 
that  has  been  made  along  that  line. 

Petroleum  is  very  usually  found  to  lie  along  an  anticlinal 
fold,  more  or  less  inclined,  the  oil  having  been  forced  into 
such  ridged  or  domed  formations  by  the  superior  gravity  of 
water  pressure  behind  it.  A  natural  sequence  of  this  is  that, 
when  an  oil  well  becomes  exhausted,  the  oil  is  frequently 
succeeded  by  a  flow  of  water — often  salt. 

This  frequent  presence  of  salt  water  with  petroleum  lends 
colour  to  the  supposition  that  petroleum  is  of  marine  origin, 
and  formed  by  the  action  of  heat  and  pressure  on  marine 
organisms  of  animal  or  vegetable  origin. 

Porous  "strata  are  the  most  favourable  for  the  storage  of  oil 
owing  to  their  porosity.  When  overlaid  by  impermeable  beds 
of  clay,  gas  usually  accompanies  the  oil  when  first  struck. 
When  oil  occurs  in  clay,  as  in  the  oil  shales  of  Scotland  and  of 
New  South  Wales  and  in  the  Kimeridge  Clay  of  England,  the 
clay  has  merely  absorbed  the  oil  and  holds  but  a  comparatively 
small  quantity.  The  gas  has  often  escaped.  At  Heathfield  in 

28 


THE   GEOLOGY   OF   PETROLEUM 


Sussex  the  author  bored  a  well  in  1896  for  the  London  and 
Brighton  Railway  Co.,  upon  an  anticlinal  fold  of  the  Weald. 
Very  little  water  was  found,  but  gas  at  considerable  pressure 
had  been  enclosed  by  the  impermeable  dome,  and  has  since 
been  used  to  light  the  Company's  station.  But  the  oil  with 
which  it  is  associated  is  probably  only  that  small  amount  which 
was  proved  by  the  subwealden  boring  in  Limekiln  Wood, 
near  Battle,  and  has  long  been  known  to  be  contained  in  the 
Kimeridge  Clay  which  has  for  years  been  worked  for  oil  at 
Wareham  in  Dorsetshire. 

Surprise  is  sometimes  expressed  that  within  a  small  distance 
of  each  other  some  borings  yield  good  supplies  of  oil,  while 
others  close  by  are  barren.  But  we  cannot  know  the  hidden 
geology  of  any  area,  even  if  the  surrounding  outcrops  appear 
to  point  to  continuity  and  conformity.  Thus  who  was  to 
know,  until  the  classical  bore-hole  was  made  at  Meux's  brewery 
in  Tottenham  Court  Road,  London,  that  when  the  lower 
Greensand  was  being  deposited  in  a  salt  sea  the  site  of  London 
was  an  uprising  above  sea  level  of  a  mound  or  ridge  of  Devonian 
rock,  so  that  the  greensand  Sea  extended  only  to  a  point  under 
the  above  brewery.  Take  the  map  of  Ireland  and  look  at  the 
deep  indentations  of  the  south-west  coast,  Bantry  Bay,  Dingle 
Bay,  the  Kenmare  River  and  Dunmanus  Bay.  Imagine  this 
area  gradually  to  sink  deep  below  sea  level  and  to  be  wholly 
covered  with  clay.  Then  according  as  a  bore- hole  was  put 
down  from  the  surface  above  what  is  now  hard  rock,  or  above 
what  is  now  the  sea,  so  would  the  thickness  of  the  surface 
stratum  of  clay  vary  by  many  hundred  feet.  The  cliffs  being 
vertical  in  places,  this  difference  of  thickness  might  occur  in  a 
distance  of  a  few  feet.  A  fault  would  possibly  be  declared  to 
exist,  whereas  the  difference  would  merely  be  due  to  the  ancient 
marine  action,  which  has  left  standing  these  upturned  hard 
rocks  whose  synclinal  folds  may  have  an  equal  dip  below  the 
waves  that  the  anticlinal  folds  have  a  rise  above  them.  Such 
natural  features  as  appear  in  present  day  surface  geology  may 
be  fairly  assumed  to  have  formed  the  ancient  floor  on  which 
more  recent  strata  have  since  been  deposited. 

The  presence  of  oil  in  any  stratum  does  not  necessarily  in- 
dicate that  it  was  formed  in  that  stratum.  It  may  have  found 
its  way  there  by  reason  of  the  superincumbent  pressure  of  the 
overlying  strata,  or  it  may  have  reached  such  stratum  vaporized 
by  heat  and  there  condensed  to  liquid.  Or  again,  it  may  have 
been  forced  to  leave  some  earlier  location,  no  matter  how  it 
reached  such  earlier  location,  by  the  superior  pressure  of  water. 
Water  indeed  has  much  to  do  with  what,  for  lack  of  a  better 


t;3J>-;::: 


FUEL  AND  ITS  APPARATUS 


term,  may  be  called  the  hydrogeology  of  petroleum.  When  a 
petroleum  well  gushes,  it  does  so  because  the  oil  is  being  pressed 
upon  by  water,  which,  but  for  the  presence  of  oil,  would  itself 
rise  near  to  or  above  the  surface. 

A  case  may  be  pictured,  as  in  Fig  0,  where  a  porous  stratum  m 
is  fed  with  water  from  the  surface  at  8.  This  water  escapes 
by  some  opening  to  the  surface,  or  it  may  flow  away  in  the 
direction  of  c  to  some  surface  spring  at  the  level  of  the  water 
line  marked  W.L.I. 

In  the  anticlinal  fold  or  dome  under  the  point  A  there  would 
be  a  reservoir  of  oil  under  a  water  pressure  equal  to  P.  A  bore- 
hole at  A,  right  above  the  ridge  of  this  buried  anticline,  would 


W.L 


WL  2 


W.L  3 


Fig.  0.  —  HYPOTHETICAL  SECTION  OF  OIL-BEARING  STRATIFICATION. 


allow  this  pool  of  oil  to  escape  at  the  surface  as  a  gusher. 
And  when  all  the  oil  had  escaped  the  well  would  yield  water. 

Similarly  a  boring  at  E  would  yield  oil  equally  freely,  but 
water  would  follow  while  still  the  crown  of  the  dome  contained 
oil  above  the  upper  dotted  line.  A  well  at  G  would  yield 
water  from  the  first,  while  at  D  neither  oil  nor  water  would  be 
found  unless  the  bore-hole  was  carried  down  below  W.L.I. 

Let  all  the  conditions  remain  the  same,  except  that  the  water 
level  stands  at  the  line  W.L.  2.  The  same  results  would  happen, 
except  that  the  wells  would  not  yield  above  the  surface.  They 
would  be  known  as  pumping  or  baling  wells.  The  hole  D 
would  pass  through  the  water-bearing  stratum  on  to  the  left  of 
the  water  level,  and  would  therefore  be  dry.  It  is  easy  to 
multiply  these  assumed  geological  forms  in  order  to  account  for 
every  peculiarity  that  may  be  met  with. 

Readers  can  picture  for  themselves  the  very  much  wider 
fields  over  which  boring  would  be  successful  if  the  water  only 


THE  GEOLOGY  OF  PETROLEUM       31 

stood  at  W.L.3,  for  with  suitable  stratification  to  the  right  of 
c,  it  would  be  possible  for  oil  to  fill  the  stratum  m  even  to  the 
surface,  and  the  whole  of  the  oil  could  be  finally  baled,  and 
without  meeting  with  water.  Nor  is  it  necessary  to  assume  the 
existence  of  a  buried  anticlinal.  A  mere  frustrum  may  alone 
have  been  left  by  surface  denudation  and  borings  along  the 
side  slopes  of  this  frustrum  may  reach  oil.  But  a  gushing  well 
demands  artesian  pressure  or  gas  as  its  acting  force. 

The  boring  of  an  oil  well  is  complicated  by  the  occurrence 
of  water-bearing  strata  above  the  oil-bearing  stratum,  and  it 
is  possible  to  let  down  this  upper  water  into  the  oil  stratum 
below  in  such  a  way  as  to  force  away  the  oil  and  render 
large  areas  barren  of  oil.  Hence  the  extreme  importance  of 
shutting  out  such  water  by  casing  tubes  tightly  inserted. 

Thus  if  n  was  a  water-bearing  stratum  the  casing  pipe  must 
pass  through  this  and  enter  well  into  an  impermeable  stratum 
below,  such  as  let  it  be  supposed  i  may  be. 

Where  the  slopes  of  an  anticline  are  steeply  inclined  the  oil 
fields  will  be  very  narrow,  and  this  explains  the  closely  spaced 
derricks  seen  on  some  fields  extended  in  a  narrow  line  along 
the  anticlinal  ridge.  Every  bore-hole  that  is  put  down  affords 
figures  from  which  the  underground  contour  of  the  rocks  can 
gradually  be  worked  up,  and  plots  of  land  gain  or  lose  in  value 
as  it  becomes  easier  to  make  definite  statements  as  to  the  depth 
to  the  oil  stratum  and  the  certainty  of  being  to  the  left  or  right 
of  points,  such  as  e,  on  which  yield  depends.  An  inspection 
of  Fig.  1  will  serve  to  show  how  easy  it  may  be  to  drive  casing 
so  as  to  shut  off  a  supply  of  oil,  and  how  it  might  also  happen 
that  instead  of  oil,  water  would  be  obtained.  It  is  also  clear 
that  a  well  may  cease  to  yield  oil  sooner  than  it  would  do  if  the 
casing  had  not  been  driven  too  far.  Thus  a  well  that  has 
ceased  to  yield  might,  on  occasion,  be  again  brought  in  by 
perforating  the  casing  at  a  suitable  horizon. 

Any  attempt  to  prove  oil  or  find  it  without  some  surface 
indication  is  considered  to  be  speculative  or  of  a  "  wild  cat  " 
order.  But  there  can  be  very  little  doubt  that  great  deposits 
of  oil  are  lying  hidden  beneath  rocks  which  are  completely 
shut  down  below  superincumbent  strata  and  have  no  outlet 
to  the  surface  by  which  they  can  give  the  faintest  indication 
of  their  presence.  Oil  exploitation  so  far  has  been  carried  out 
on  the  lines  of  working  coal  seams  from  their  outcrop  only. 
Coal  is  a  regular  geological  stratum,  and  its  presence  may  be 
inferred  at  long  distances  from  any  outcrop,  as  it  was  inferred 
at  Dover  as  a  result  of  the  artesian  boring  in  Tottenham  Court 
Road.  But  oil  is  not  a  geological  positive  fact,  for  it  may  be 


32  LIQUID  FUEL  AND  ITS  APPARATUS 

found  to-day  far  from  its  point  of  formation,  as  stated  above, 
having  suffered  lateral  or  vertical  transfer  by  the  agencies  of 
heat,  water,  gas  or  gravity.  It  is  therefore  liable  to  be  found 
in  strata  of  all  geological  periods.  If  present  in  Great  Britain  in 
serious  quantity  it  is  probable  that  it  will  only  be  found  at  very 
great  depths.  Very  little  is  known  of  the  deep-seated  rocks 
of  Britain  below  the  coal  measures,  and  the  deepest  coal  mine 
is  not  much  over  half  a  mile.  But  the  recent  strata  of  the  south- 
east of  England  are  now  known  to  He  unexpectedly  and  uncon- 
f  ormably  upon  ancient  rocks  of  Devonian  and  Silurian  and  also 
Carboniferous  age.  So  that  the  unexpected  may  yet  happen 
in  the  shape  of  a  petroleum  field  in  Great  Britain,  possibly 
in  the  deep-seated  Old  Red  Series  which  are  known  to  yield 
salt  water  and  suspectedly  petroliferous. 


Petroleum  Drilling  and  Pumping 

Oil  wells  are  bored  by  the  aid  of  a  derrick  about  50  to  80 
feet  in  height ;  72  feet  being  a  very  usual  height.  A  derrick  is 
built  up  of  four  stout  inclined  corner  posts,  braced  by  horizon- 
tal struts  and  diagonals.  Many  modern  derricks  are  of  steel. 

The  tool  usually  employed  is  a  heavy  chisel  attached  to  a 
heavy  sinker  bar.  Sinker  bars  vary  in  size  from  2J  inches 
square  by  30  feet  long  up  to  7"  x  15  feet.  They  are  raised  and 
lowered,  by  a  rope  or  by  a  line  of  iron  rods  or  poles.  A  rapid 
up  and  down  stroke  is  given  by  means  of  a  walking  beam  to 
which  the  rope  or  rods  are  attached  by  a  long  screw  frame  or 
temper  screw,  or  by  a  chain  from  a  winch  carried  on  the  beam 
itself.  The  rope  is  let  out  by  turning  the  temper  screw  as  the 
chisel  cuts  the  rock  and  the  rods  are  lowered  gradually  by  the 
winch.  Debris  is  removed  by  drawing  up  the  line  of  tools  and 
lowering  the  sand  pump  or  shell, — a  long  tube  with  a  valve  at 
its  foot,  by  means  of  a  winch  and  rope  over  a  pulley  at  the 
top  of  the  derrick.  The  walking  beam  and  the  winch  barrel 
are  set  in  motion  by  means  of  belts  from  pulleys  on  shafts 
driven  by  an  engine,  such  belts  being  slack,  but  tightened  up 
to  working  tension  by  pressure  from  lever-actuated  jockey 
pulleys.  Other  levers  control  the  band  brakes  which  hold  the 
mechanism  securely  at  rest  when  needed.  A  second  winch 
raises  and  lowers  the  casing  tubes.  In  Russia  wells  may  start 
with  casing  as  big  as  24  or  36  inches  diameter.  In  America 
wells  are  usually  8  and  10  inches,  finishing  as  small  as  4  inches. 

Another  system  of  boring  is  the  rotary  system,  by  which  the 
casing  itself  forms  the  tool  and  is  rotated  by  gearing  at  the 


THE  GEOLOGY  OF  PETROLEUM       33 

surface  and  sinks  through  loose  strata  by  the  aid  of  a  flush  of 
water  forced  down  the  casing,  and  escaping  into  the  strata 
through  which  the  casing  penetrates,  or  making  its  way  to  the 
surface  outside  the  pipe. 

Boring  operations  are  simple  while  things  go  well,  but  ropes 
and  rods  break,  the  bore-hole  walls  fall  in,  the  chisel  is  jammed 
fast  or  the  casing  collapses  under  heavy  pressure  from  without, 
and  a  great  variety  of  salvage  or  fishing  tools  are  made  to  combat 
these  contingencies.  Hence  the  need  for  strength  and  the 
reliability  given  by  Low-moor  or  Farnley  iron  for  special  items. 

Owing  to  the  inflammability  of  the  gas  and  oil  which  a  well 
may  yield,  the  boiler  is  kept  well  back  from  the  derrick,  and  the 
engine  is  connected  by  a  long  belt  to  the  mechanism  of  the  rig. 

Derricks  are  now  frequently  formed  entirely  of  steel. 

Casing  consists  of  lengths  of  steel  pipe  screwed  to  a  butt 
joint  and  socketed.  They  are  used  in  random  lengths,  unlike 
the  English  artesian  system  of  using  dead  lengths  of  10  or  12 
feet,  which  render  it  so  much  easier  to  know  the  exact  depths 
to  which  casing  has  been  driven. 

When  oil  has  been  obtained,  but  does  not  flow  to  the  surface, 
it  is  raised  by  the  baler,  a  long  pipe  with  a  valve  at  its  base, 
which  is  lowered  by  a  winch  and  rope  into  the  oil  and  hauled 
up  full  of  oil.  Baling  may  be  continuous  night  and  day  at  maxi- 
mum possible  yield,  or,  if  supplies  are  poor,  baling  will  be  done 
morning  and  evening  for  as  long  as  desirable,  the  oil  accumulat- 
ing in  the  day  and  night  between  baling  times. 

Or  pumps  may  be  employed,  and  on  some  fields  many  pumps 
are  worked  from  one  central  engine  by  means  of  a  crank  rotat- 
ing on  a  vertical  spindle  and  hauling  upon  a  number  of  tension 
ropes  attached  to  the  pumps  like  spokes  radiating  from  a  central 
hub.  When  the  oil  is  not  too  deep  below  surface  the  air  lift 
pump  may  be  employed,  though  this  is  expensive  to  work,  owing 
to  the  general  low  efficiency  of  compressed  air,  but  it  has  some 
very  serious  advantages. 

Given  that  the  oil  is  present  in  a  well,  more  can  be  raised  by 
the  air  lift  in  a  given  time  than  by  any  other  system.  This  is 
specially  valuable  where  there  is  a  free  supply  of  oil  and  the 
well  is  of  small  diameter. 

There  are  no  moving  parts  down  the  well.  Any  number  of 
wells  can  be  pumped  from  a  single  power  station,  the  compressed 
air  being  carried  to  each  well  by  a  branch  from  an  air  main. 

The  central  power  station  may  be  at  any  distance  from  the 
wells,  so  avoiding  all  risk  of  fire. 

Oil  containing  sand  can  be  raised  with  ease.  Sand  causes  a 
good  deal  of  wear  in  pumps.  Both  pumps  and  balers  can  be 

c 


34  LIQUID  FUEL  AND  ITS  APPARATUS 

worked  with  safety  by  enclosed  electric  motors,  the  current 
being  brought  from  a  safely  distant  power-generating  station. 

In  using  boring  systems  which  involve  the  employment  of 
water  flushing  for  debris  removal,  there  is  risk  in  some  circum- 
stances that  the  oil  when  reached  may  be  driven  away  by  the 
water  flush  and  passed  by  without  its  presence  being  suspected. 
Engineers  should  always  be  alive  to  this  danger. 

Diamond  rotary  drilling  is  not  employed  for  oil  drilling,  for 
the  "  crowns  "  become  two  expensive  for  the  size  of  holes 
required  to  be  drilled. 

Hard  rocks  may  be  easily  penetrated  by  the  rotary  process 
with  chilled  steel  shot.  But  this  system  requires  a  flush  of 
water  with  its  possible  disadvantages.  The  ordinary  method 
with  heavy  crushing  chisel  has  the  very  serious  disadvantage 
that  it  smashes  everything  to  a  pulp,  and  destroys  the  best  of 
the  fossil  evidences  of  the  rocks  passed  through. 


CHAPTER    II 

THE    ECONOMIES   OF   LIQUID    FUEL 

IN  considering  the  application  of  liquid  fuel  every  case 
must  be  taken  by  itself  and  the  costs  evaluated.  In 
favour  of  oil  there  is,  first,  the  ease  and  rapidity  with  which 
a  liquid  can  be  taken  into  store  and  delivered  to  the  bunkers 
of  a  ship  or  the  tank  of  a  locomotive.  Next  there  is  the 
economy  of  labour^  which  may  be  almost  nil  in  case  of  a  single 
boiler  with  one  attendant  to  the  engine  and  boiler,  or  it  may 
be  very  great  where  there  are  many  boilers. 

The  superior  calorific  power  of  oil  must  then  be  equated 
with  the  price,  and  the  cost  per  unit  of  evaporation  found  from 
this. 

The  removal  of  cinders  and  ash  may  or  may  not  be  a  matter 
of  cost,  according  to  the  demand  for  them  locally. 

Liquid  fuel  possesses  great  elasticity  of  use  and  fits  well 
with  sudden  and  varied  demands  for  power.  Hence  its  value 
in  railroad  work,  electric  light  work,  and  other  power  stations 
where  loads  vary  greatly. 

Where  the  mixed  system  is  employed,  as  with  the  Great 
Eastern  Railway,  the  mere  question  of  economy,  as  based  on 
the  actual  weight  of  fuel  consumed,  is  to  be  found  as  follows  : 

A  locomotive  consumes  N  units  of  coal  per  unit  distance. 
When    running  with    coal  and   oil,  it   is   found    to    consume 
M  units  of  coal. 
0       „       „    oil. 
The  price  of  coal  is  y  ;  of  oil  x  per  unit. 


Then  O  x  M  x  „  £  N    x  -        or  ,  L  -*- 


The  cost  of  oil  is  largely  a  matter  of  carriage.  What  costs 
three  francs  =  2s.  6d.  per  ton  at  Baku  costs  185  francs  = 
£7  8s.  6d.  in  France.  The  difference  of  182  francs  is  made  up 
of  railway  and  sea  carriage,  handling,  customs,  warehousing. 
The  customs  stand  for  ninety  francs,  so  that  the  same  oil  at 
an  English  port  should  not  cost  over  £3  16s. 

35 


36  LIQUID  FUEL  AND  ITS  APPARATUS 

American  residues  cost  five  to  six  francs  more  than  Russian 
mazut,  whence  MM.  Colonner  and  Lordier,  who  give  the  above 
figures,  dismiss  oil  as  an  economical  fuel  in  France  pending  the 
reduction  of  the  tariff. 

On  the  Southern  Pacific  Railroad  the  relative  evapora- 
tion of  oil  and  coal  is  365  :  274,  or  33  per  cent,  in  favour  of 
oil. 

On  the  International  and  Great  Northern  four  barrels  of  oil 
proved  more  than  equal  to  a  ton  of  coal,  and  at  12s.  6d.  per 
ton  and  2s.  4d.  per  barrel  the  economy  of  oil  was  13  to  14  per 
cent.,  including  the  economy  of  handling  and  storing. 

To  produce  1,000  units  of  steam,  coal  gives  out  more  carbonic 
acid  than  oil,  though  the  oil  destroys  quite  as  much  oxygen 
and  reduces  the  life-supporting  power  of  the  air  to  probably 
equal  extent.  So  long  as  combustion  is  perfect  and  no  actual 
poisons  are  made,  there  is  not  much  to  choose  between  the 
two  fuels  beyond  their  sulphur  contents.  As  regards  the 
safety  of  oil,  it  has  been  shown  that  oil  with  117°C.  =  239°F. 
flash-point  did  not  ignite  if  fired  at  with  shell,  nor  did 
dynamite  exploded  in  a  reservoir  of  this  oil  do  more  than  throw 
up  jets  of  oil  which  did  not  ignite. 

Any  danger  with  liquid  fuels  is  with  the  oils  which  have  not 
parted  with  their  inflammable  and  volatile  gases.  This  is  a 
danger  with  oils  when  used  absolutely  crude.  Purged  of 
these  portions,  however,  oil  is  safe,  and,  moreover,  unlike  coal, 
it  contains  no  power  of  spontaneous  combustion.  Though 
it  is  claimed  by  some  that  oil  does  not  deteriorate  if  kept  in 
tanks,  others  do  claim  that  a  certain  deterioration  is  produced 
which  renders  it  difficult  to  atomize,  the  oil  becoming  more 
thick  and  viscid. 

In  Russia  circular  atomizers  are  often  employed  which  give 
out  a  large  hollow  flame.  The  Bereznef  atomizer,  is  one  of 
these.  They  have  the  disadvantage  of  being  out  of  reach  in 
the  middle  of  the  fire  of  a  locomotive,  and  they  become  burned 
also  through  being  in  such  close  contact  with  the  flame. 

Steam  enters  below  a  central  disc,  and  oil  flows  under  a 
head  of  two  to  three  metres  on  the  upper  side  of  the  disc. 

The  advantage  of  this  form  is  said  to  be  its  constant  out- 
put. 

Too  much  mazut  produces  smoke,  too  much  steam  is  waste- 
ful. There  is  a  certain  fixed  ratio  of  oil  and  steam  to  give  the 
best  result.  The  Issai'ef  atomizer,  which  resembles  the  Berez- 
nef, will  feed  50  to  100  kilos,  of  oil  per  hour  (110  to  220  lb.), 
and  it  consumes  nearly  0-4  kilos.  —  88  lb.  of  steam  at  4  to  5 
atmospheres  pressure  per  kilo,  of  oil  (2-2  lb.).  The  table, 


THE  ECONOMIES   OF  LIQUID  FUEL 


37 


DATA. 

NO.  OF  TEST. 

1 
3  atomizers 
Beieznef 

2 
4  atomizers 
Kroupka 

3 

1  atomizer 
Bereznef 

4 
3  atomizers 
Bereznef 

5 
3  atomizers 
Baschinino 

Duration  of  trial.     Hours    . 
Total  kilos,  of  oil  consumed. 
Mean  boiler  pressures  in  at- 
mospheres    

12hrs. 
2193k. 

4-5 

41°C. 

31,096 

29,140 

14-17 
13-28 
0-987 

13-1 
120°C. 
132°C. 
27°C. 

185 

lOh  30m. 
795-7 

5-0 

38°C. 
11,912 

11,122 

149 
139 
1-131 

15-81 

85° 
1303 

27° 

0422 
60 

lOh  30.li. 
1,104 

4-5 

46  6°C. 
16,232 

15,071 

14-7 
1365 
1-569 

21-42 
87-3° 
139-1° 
20° 

0-364 
60 

7  hrs. 
1,183 

5-0 

19  2°C. 
16,284 

15,805 

13-76 
13-36 
1-469 

19-633 
68-9° 
90° 

27° 

115 

9  hrs. 
1,183 

4-75 

20-2°C. 
16,832 

16,310 

14-22 
13-78 
1-143 

15-758 
64-6° 
80° 
26-8° 

115 

Mean    temperature    of    feed 
water      

Litres  of  water  fed  to  boilers 
Kilograms  of  water  fed  to 
boilers    . 

Kilograms  of  steam  produced 
at   feed   temperature   per 
kilo  of  oil   .... 

Kilograms  of  steam  produced 
from  0°C.  per  kilo  of  oil    . 
Oil  per  hour  per  square  metre 
of  grate  surface.     Kilos.  . 
Steam  per  hour  per  square 
metre    of    grate    surface. 
Kilos  

Tempera-  j°*  feed  water       . 
ture       1  of  chimney  gas    . 
(  of  air  above  boilers 
Atomizing  steam  per  kilo  of 
oil.     Kilos  
Heating  surface.     Sq.  metres 

1     square   metre  =  10  -76    square    feet.     Kilograms    per    square    metre 
-T-  5=  pounds  per  square  foot  nearly. 

above,  is  given  by  M.  Keller,  of  Moscow,  as  the  result  of 
tests  made  with  various  atomizers. 

M.  Bertin,  in  dealing  with  the  efficiency  of  liquid  fuels, 
points  out  that  a  fuel  containing  85  per  cent,  of  carbon  and 
14  per  cent,  of  hydrogen,  will  consume  the  oxygen  of  7-56 
cubic  metres  of  air  to  satisfy  the  carbon,  and  of  2-72  metres  to 
satisfy  the  hydrogen,  or  10-28  cubic  metres  in  all.  By  adding 
40  per  cent,  excess  of  air,  or  14-4  cubic  metres  —18-7  kilos. 
of  air  per  kilo,  of  oil,  then  combustion  will  be  perfect  and 
smokeless. 

The  Author's  own  figure  for  the  weight  of  air  chemically 
necessary  for  the  above  sample  would  be  14'  7  nearly,  and  40 
per  cent,  excess  would  increase  this  to  20-56.  M.  Bertin's 
figure  of  18-7  appears  to  represent  about  27  per  cent,  air  excess. 

The  theoretical  temperature  of  combustion  will  be  — 


(18-7 


38  LIQUID  FUEL  AND  ITS  APPARATUS 

If  the  gases  leave  the  boiler  at  300°C.  —  572°F.  the  loss  of 
heat  will  be  -^— — -  =  12-10  per  cent,  of  the  total,  which  is  equi- 
valent to  an  increased  efficiency  of  6-65  per  cent,  as  compared 
with  coal.  He  further  estimates  a  gain  of  1-9  per  cent,  over 
coal  in  the  absence  of  ashes  and  their  cooling  (onboard  ships). 

The  efficiency  of  a  boiler  estimted  at  75  per  cent,  for  coal, 
becomes  0-835  for  oil  firing,  or  0-75  +  0-0665  +  0-019  — 
0-835. 

But  good  combustion  and  utilization  still  further  favour  oil 

•835 
in  the  ratio          —  1-28  —  m  ;    m  becoming  then  r  =  1-20  x 

1-28  =  1-53  ;  the  figure  1-20  being  the  chemical  ratio  of  power 
of  coal  and  oil.  In  Torpedo-boat  No.  62  (French)  M.  Bertin, 
however,  only  obtained  m  —  I'll  and  r  =  1-33.  The  causes 
of  the  difference  are  found  in  the  nature  of  the  flame  of  oil, 
which  has  less  radiating  power  than  the  flame  of  coal,  and  the 
powerful  effect  of  the  directly  heated  coal  furnace  is  sacrificed, 
and  to  secure  the  same  results  an  undesirable  extension  of  heat- 
ing surface  would  be  necessary. 

Secondly,  the  flame  of  oil  is  long  if  care  be  not  taken  suitably 
to  arrange  the  burners.  It  may  pass  between  the  tubes  and 
become  extinguished,  and  the  gases  partly  burned  may  even 
relight  in  the  chimney.  The  chemical  action  and  reactions  of  a 
burning  spray  of  oil  may  be  very  much  complicated  by  disso- 
ciation or  even  by  exothermic  formations,  which  may  delay 
heat  production.  Later  when  combustion  becomes  active  as 
shown  by  the  light  giving  power  of  the  flames,  it  will  be  more  or 
less  rapid  according  to  the  perfection  of  air  admixture,  and  will 
last  for  a  time  =  t,  during  which  the  jet,  travelling  at  a  high 
velocity,  v,  passes  through  a  distance  L  =  vt,  which  may  be 
yards  in  length. 

Thus  the  course  of  the  gas  must  be  long,  or  it  may  escape  too 
hot  to  the  chimney.  Hence  arises  the  necessity  of  cutting  short 
the  flame  by  early  admixture  and  high  temperature,  so  as  not 
to  lose  the  benefit  of  the  boiler-heating  surface. 

It  is  for  this  purpose  that  in  most  successful  oil-burning  fur- 
naces the  jet  of  atomized  oil  is  directed  upon  a  brick  obstruction 
of  some  kind  so  as  to  spread  the  flames  and  cause  them  to  fill 
the  furnace  space  and  lick  round  the  plate  surface.  Locomotive 
fireboxes  may  be  studied,  as  in  Fig.  26  to  show  how  this  effect  is 
secured  before  the  gases  escape  to  the  small  tubes. 

General  Prinicples  of  Liquid  Combustion. — A  review  of   the 


THE  ECONOMIES   OF  LIQUID  FUEL  39 

whole  subject,  in  the  light  of  chemical  knowledge,  of  the  claims 
of  manufacturers  and  of  users  of  liquid  fuel,  shows  that  success- 
fully to  burn  a  liquid  it  must  be  finely  pulverized,  to  do  which 
it  must  be  heated  sufficiently  to  destroy  its  viscosity  and  en- 
able the  spraying  agent,  air  or  steam,  to  tear  it  up  and  disperse 
it  in  a  fine  spray  intimately  mixed  with  air.  The  correct 
amount  of  air  must  be  admitted  to  burn  the  liquid,  and  this  is 
one  of  the  advantages  of  employing  air  as  the  atomizing  agent. 
Where  sufficient  air  cannot  be  introduced  with  the  fuel,  it 
must  be  admitted  from  below,  as  through  grate  bars  covered  with 
broken  bricks.  Steam,  preferably  superheated,  is  the  most 
convenient  to  employ  as  the  atomizing  agent,  but  on  the  salt 
seas  has  the  disadvantage  of  wasting  from  3  to  5  per  cent, 
of  the  steam  made  by  the  boilers,  and  this  loss  must  be  made 
good  by  evaporators. 

As  with  bituminous  coal,  which,  like  oil,  is  a  complex 
hydrocarbon,  liquid  fuel  should  be  burned  in  furnaces  more 
or  less  protected  from  immediate  loss  of  heat  to  the  boiler 
surfaces  by  means  of  linings  or  baffles  of  firebrick.  Liquid 
fuel,  however,  is  more  easy  to  burn  completely  than  is  coal, 
because  it  can  be  more  intimately  mixed  with  the  necessary 
air.  The  interior  of  a  combustion  chamber  should  show  a 
clear  white  incandescence  with  little  apparent  flame,  and  no 
smoke  or  unburned  gases  coming  from  the  chimney.  If  looked 
into  through  a  piece  of  violet-coloured  glass,  the  interior  of  the 
combustion  chamber  with  its  brick  linings  should  show  a  light 
lavender  colour  indicative  of  perfect  combustion,  with  the  pro- 
duction of  actinic  rays  indicative  of  high  chemical  action.  A 
chilled  fire,  such  as  is  produced  where  a  boiler  is  placed  close 
upon  the  furnace  of  a  coal  fire,  will  show  very  little  light  indeed 
through  a  violet  glass,  its  flames  being  cut  down  from  several 
feet  in  length  to  a  few  inches  only  in  many  instances,  the  flames 
of  yellow  and  reddish  intensity  being  resolved  into  streams  of 
dun-coloured  gas  which  throw  off  no  light  of  sufficient  actinic 
power  to  penetrate  the  glass. 

Much  difference  of  opinion  exists  in  regard  to  the  flash-point 
of  the  oil  to  be  used.  Crude  oil  is  so  widely  different  a  product, 
according  as  it  comes  from  one  or  another  locality,  that  no  rule 
can  be  laid  down  as  to  its  safety  or  otherwise.  Those  crude 
oils  which,  like  the  Pennsylvania  oil,  give  a  large  proportion 
of  gasolene  and  other  volatile  compounds,  are  not  used  in  their 
crude  form  because  they  pay  better  to  refine,  the  heavier  resi- 
duum being  used  as  fuel  and  being  much  safer.  The  use  of 
volatile  liquids  is  only  undesirable  on  the  score  of  safety. 
Some  of  the  crude  oils,  as  for  example  those  of  the  Beaumont 


40  LIQUID  KIEL  ANt>  ITS  APPABATtTS 

field  of  Texas,  contain  so  little  of  the  lighter  oils  that  they  are 
used  as  fuel  in  their  crude  form.  The  one  thing  to  note  is  that 
the  more  highly  volatile  oils  have  an  element  of  danger  from 
which  the  heavy  oils  are  free,  and  this  danger  intensifies  the 
results  of  every  possible  accident  that  may  occur,  especially  such 
as  arise  from  rupture  of  an  overhead  tank  and  the  gravitation 
of  the  oil  to  lower  points.  The  whole  question  is  really  very 
simple,  and  resolves  itself  into  an  intimate  mixture  with  air  in 
sufficient  quantity  and  a  proper  conservation  of  the  temperature 
pending  full  combustion.  Fortunately  for  liquid  fuels,  these 
items  are  not  only  easy  to  realize,  but  failure,  when  they  are 
not  realized,  is  far  more  disastrous  and  complete  than  in  the 
case  of  solid  fuels.  Hence  the  really  simple  problem  of  burning 
bituminous  coal  has  never  been  properly  solved,  except  in  a  few 
cases.  At  the  same  time  it  is  easy  of  solution,  but  if  not  solved 
it  does  not  produce  the  same  bad  effects  as  does  the  faulty  com- 
bustion of  liquid  fuel.  In  regard  to  this  question,  the  Author 
would  like  to  point  out  that,  where  coal  is  burned  in  a  refractory 
furnace,  it  should  be  capable  of  burning  perfectly,  with  less 
excess  of  air,  and  coal  ought  to  give  results  more  nearly  ap- 
proaching its  true  value  than  it  does  do  in  ordinary  faulty 
daily  practice.  Probably  all  the  comparisons  given  in  this 
book,  except,  perhaps  to  some  extent  those  of  locomotives, 
are  too  favourable  to  liquid  fuel,  which  is  supplied  with  those 
essentials  of  perfect  combustion  that  are  withheld  from  coal. 

This  question  of  refractory  linings  is  essential,  and  it  is 
secured  by  bridge  walls,  overarching  and,  where  fire-bars  are 
left  in  place,  by  covering  these  with  broken  firebrick  or  by  whole 
bricks  laid  on  edge. 

It  does  not  seem  possible  to  introduce  all  the  necessary  air 
with  the  fuel.  A  chemical  minimum  of  fifteen  pounds  of  air- 
is  necessary  to  supply  the  oxygen  for  the  average  hydrocarbon 
liquids,  but  probably  at  least  5  to  10  per  cent,  excess  is  required 
in  the  best  practice,  and  this  must  come  in  below  the  oil  spray, 
and  should  not  be  introduced  in  a  single  large  stream,  but 
divided  up  into  numerous  fine  streams  through  perforated  plates, 
or  through  a  mass  of  broken  bricks  or  loosely  laid  brickwork. 
In  Fig.  51  is  shown  the  arrangements  of  air  admission  at  the 
floor  of  a  water- tube  boiler  furnace  which  is  in  the  right  direc- 
tion. The  Weir  boiler,  Fig.  7,  p.  121  is  also  suitably  arranged 
for  liquid  fuel,  as  regards  the  lining  of  the  furnace  and  combus- 
tion-chamber. Where  liquid  fuel  is  used  alone  the  fire-grate 
would  be  covered  with  bricks  laid  on  edge  or  simply  broken  into 
pieces  of  2-inch  cubes,  and  the  atomizers  would  be  arranged 
similarly  to  those  of  Fig.  51.  The  general  conditions  that  have 


THE  ECONOMIES  OF  LIQUID  FUEL  41 

been  evolved  are  well  shown  in  the  various  locomotive  and 
stationary  boiler  furnaces  illustrated  in  Part  II. 

In  the  Weir  small  water- tube  boiler  the  sides  of  the  y\ -shape 
furnace  are  lined  in  firebrick  blocks  which  are  threaded  upon 
the  middle  widely  spaced  tubes  which  form  the  walls  of  the 
furnace  proper. 

The  first  row  of  the  main  body  of  tubes  is  similarly  protected 
to  form  a  refractory  wall  for  the  combustion  chamber.  Thus 
both  the  furnace  and  combustion-chamber  are  fully  refractory 
on  two  sides.  Such  a  boiler  as  this  can  be  worked  with  coal 
entirely,  with  oil  alone,  or  upon  the  mixed  system,  the  brick 
linings  enabling  combustion  to  be  carried  out  with  smokeless 
and  economical  perfection. 

s  By  means  of  sight-holes  the  furnace  can  be  examined,  and  the 
admission  of  air  gradually  increased  until  the  gases  become 
clear,  clean,  brightly  incandescent  red,  and  the  opposite  end  of 
the  furnace  shows  up  clearly.  So  long  as  there  is  smoke-forma- 
tion the  opposite  brickwork  cannot  be  seen.  As  soon  as  com- 
bustion is  perfect  it  appears  clear  and  bright  red,  and  the  air 
should  then  be  cut  down  in  quantity  until  an  occasional  streak 
of  dark-coloured  gas  begins  to  show,  thus  proving  that  under 
the  conditions  of  the  furnace  the  air  has  been  reduced  to  a 
possible  minimum. 

Under  some  conditions  of  boilers  it  would  appear  that  to 
ensure  smokeless  combustion  of  liquid  fuel,  not  more  than  2  to 
3  Ib.  should  be  consumed  per  hour  per  cubic  foot  of  combustion 
space.  This  will  have  considerable  bearing  upon  the  question  of 
furnaces  with  or  without  fire-grates,  the  latter  type  more  easily 
securing  the  requisite  volume.  The  above  figure  may  be  borne 
in  mind  when  considering  the  question  of  furnace  dimensions. 
More  recent  practice  is  claimed  to  give  a  nearly  smokeless  com- 
bustion with  a  rate  of  20  Ib.  of  oil  per  cubic  foot  per  hour. 

The  term  liquid  fuel  is  herein  limited  to — 

1.  Coal  gas  tar,  creosote,  coke  oven  tars,  blast  furnace  tars, 

and  the  tar  from  oil  gas  manufacture  and  other  pro- 
ducts of  the  destructive  distillation  of  fuels,  including 
the  more  volatile  naphthas. 

2.  Petroleum  and  other  mineral  oils  found  liquid  in  nature  or 

distilled  from  bituminous  shales. 

In  a  work  of  this  nature,  also,  it  would  not  be  possible  to 
take  notice  of  all  the  uses  of  liquid  fuels.  For  the  purposes 
of  this  book,  therefore,  liquid  fuel  includes  the  products  under 
sections  1  and  2  which  do  not  possess  a  volatility  or  refinement 
greater  than  those  of  the  heavy  paraffin  series  or  lighting  oils. 
/  The  crude  mineral  oils  of  course  contain  such  volatile  consti- 


42  LIQUID  FUEL  AND  ITS  APPARATUS 

tuents,  and  may  be  used  in  their  crude  form,  but  usually  the 
superior  value  of  the  distillates  leads  to  these  being  first  sepa- 
ated,  the  coarse  residuum  known  as  astatki  or  mazut  being  the 
oil  so  much  used  as  fuel.  Having  been  deprived  of  its  more 
volatile  portions,  it  is  safer  to  carry  and  to  use. 

A  liquid  will  not  burn  when  cold,  and  cannot  be  ignited  in 
mass.  If  heated  to  the  point  of  ebullition  and  supplied  with 
air,  it  will  of  course  burn  fiercely  and  uncontrollably.  The 
art  of  burning  liquid  fuel  consists  in  heating  only  the  portion 
which  is  to  be  immediately  burned  and  exposing  it  to  contact 
with  air.  Unlike  coal,  it  is  not  possible  to  burn  it  at  many  sur- 
faces. A  coal  fire  is  made  up  of  many  pieces  of  coal,  each  burn- 
ing over  its  whole  surface.  /  Liquid  fuel  will  not  lie  on  a  grate  in 
separate  pieces.  If,  however,  a  layer  of  liquid  were  heated  to 
vaporizing  point,  or  nearly  so,  on  a  finely  perforated  plate, 
and  highly  heated  air  were  forced  through  the  perforations,  the 
liquid  would  no  doubt  burn  freely  with  strong  flame,  but  the 
mass  of  heated  liquid  would  be  difficult  to  control.  Hence  in 
practice  we  arrive  at  those  systems  which  employ  a  jet  of  air  or 
steam  to  split  up  a  stream  of  liquid  into  fine  globules  in  presence 
of  a  sufficient  supply  to  air.  Each  globule  burns  superficially 
and  becomes  heated  by  its  own  combustion  and  the  general 
heat  of  the  furnace,  and  this  principle  appears  to  be  the  best 
and  most  effective  method  of  burning  liquids.  Indeed,  it  is 
perhaps  the  best  method  of  burning  anything,  first  to  reduce 
it  into  particles  so  fine  that  their  bulk  bears  a  small  ratio  to 
their  surface  area,  whereby  each  particle  is  brought  close  to  the 
air  which  it  requires. 

Atomizing. 

The  necessity  for  atomizing  arises  purely  from  the  insufficient 
surface  area  of  the  fuel  otherwise  treated.  A  fire  composed  of 
lumps  of  coal  is  full  of  interstices,  and  the  area  of  the  fuel  ex- 
posed to  air  is  much  greater  than  the  area  of  the  fire-grate. 

Liquid  fuel  would  fall  through  the  grate.  It  cannot  be  burned 
on  a  flat  surface,  because,  being  liquid,  it  tends  to  flow  together 
and  presents  only  an  upper  surface  to  the  air.  The  use  of 
trough-shaped  bars  along  which  the  liquid  flows  and  through 
which  streams  of  air  are  admitted,  does  not  get  over  the  diffi- 
culty of  small  exposure  of  surface. 

There  is  no  incandescent  mass  through  which  air  is  flowing 
to  carry  off  the  fuel  in  a  burned  state  and  to  maintain  the  mass 
incandescent.  If  the  whole  of  the  liquid  mass  in  a  furnace  did 
become  incandescent,  or  even  approached  that  point,  it  would 


THE  ECONOMIES   OF  LIQUID  FUEL  43 

distil  in  the  form  of  vapour,  and,  if  provided  with  air,  would  burn 
away  uncontrollably,  probably  with  great  evolution  of  smoke. 
The  more  easily  combustible  or  volatile  portions  would  dis- 
appear first  and  the  remainder  would  probably  be  left  over  un- 
consumed.  Thus  if  the  fire  is  to  be  controllable,  the  fuel  must 
be  supplied  as  it  is  consumed,  so  that  at  no  time  is  there  any 
serious  amount  of  burning  fuel  in  the  furnace,  and  the  produc- 
tion of  steam  is  at  once  regulated  by  a  simple  regulation  of  the 
fuel  supply.  This  end  is  secured  by  atomizing  the  fuel  and 
discharging  it  into  the  furnace  mixed  with  air,  so  that  each 
atom  of  fuel  is  in  contact  with  air,  and  combustion  is  easily 
effected.  It  will  be  found  that  with  all  the  heavy  liquid  fuels 
atomizing  is  essential. 

+ 

Vaporizing. 

With  lighter  oil,  as  the  cheap  lamp  oils  used  in  steam  motor 
cars,  the  liquid  is  supplied  through  a  coil  of  pipe  heated  by  the 
flame  itself  and  is  converted  into  vapour,  which  burns  freely 
when  mixed  with  air.  With  this  oil  it  is  not  found  that  a 
deposit  of  carbon  takes  place  in  the  retort  coil,  as  might  be  the 
case  with  heavier  oils.  The  lighter  oils  already  prepared  by 
distillation  at  a  moderate  temperature  can  thus  be  burned  with- 
out atomizing,  but,  after  all,  their  resolution  into  the  form  of 
vapour  may  be  taken  as  the  most  complete  form  of  atomization, 
and  atomization  is  really  a  substitute  for  vaporization. 


Varieties  of  Liquid  Fuel. 

In  nature  liquid  hydrocarbon  is  found  both  free  and  absorbed. 
The  free  liquid  is  obtained  from  bore-holes  put  down  to  the  oil- 
bearing  stratum.  When  not  free  it  is  obtained  by  distillation 
from  bituminous  shales.  The  latter  have  been  more  employed 
for  lighting  or  illuminating  and  lubricating  purposes.  The 
free  oil  or  petroleum  has  forced  its  way  into  consideration  as  a 
fuel,  having  been  employed  now  for  many  years  in  Russia. 
In  addition  to  the  natural  oils,  there  are  many  hydrocarbons 
formed  in  the  arts  which  have  a  high  value  as  fuel.  Of  these 
there  is  the  tar  of  the  gas-works,  a  black  viscous  liquid  which 
separates  out  from  the  gas  in  the  process  of  cooling.  It  is 
formed  in  the  hydraulic  main  and  in  the  pipe  coolers  and  con- 
densers. A  thinner  tar  is  produced  in  the  condenser  of  oil-gas 
plant  as  a  product  of  the  destructive  distillation  of  oil  in  the 
Pintsch  gas  process.  Where  blast  furnaces  are  fed  with  coal 
in  place  of  coke,  tar  is  produced  in  the  condenser  pipes  of  the 


44  LIQUID  FUEL  AND  ITS  APPARATUS 

residuals  plant,  and  in  modern  coke  ovens  a  tar  is  also  produced 
from  the  gas  driven  off  the  coal. 

Crude  petroleum  contains  many  hydrocarbon  compounds 
varying  from  the  formula  CH4  up  to  Cu,  H37,  the  general 
formulae  being  CnH2n  and  CnH2n+2  in  an  isomeric  series  of 
many  numbers.  When  subject  to  distillation  some  of  the 
compounds  are  split  up,  and  certain  compounds  have  been 
found  to  contain  as  much  as  95  per  cent,  of  carbon. 


American  Petroleum  Fuels. 

In  the  United  States  the  oils  principally  sold  for  fuel  pur- 
poses are  the  by-products  of  crude  oil ;  their  gravity  varies 
from  23°  Baume  to  about  34°. 

The  oils  of  lower  gravity  are  known  usually  under  the  name 
of  Reduced  Fuel  Oil,  and  one  of  gravity  23  was  found  to  analyse 
as  follows — 

Carbon 87-72 

Hydrogen 11-45 

Weight  per  gallon 7-62  pounds 

Weight  per  imperial  gallon 9-14       „ 

B.Th.U.  per  pound 19,800 

Calories,  per  kilo 11,000 

The  oils  of  higher  gravity  are  known  as  Distillate  Fuel  Oil, 
and  one  at  the  extreme  end  of  the  scale,  or  34  Baume,  analysed 
as  follows — 

Carbon.      . 86-19 

Hydrogen 12-51 

Weight  per  gallon  (American)    ....        7-11  pounds 

Weight  per  imperial  gallon 8-53       ,, 

B.Th.U.  per  pound 20,250 

Calories  per  kilo 11,250 

Oil  being  sold  by  the  gallon  an  oil  of  23  gravity  contains 
151,066  B.Th.U.,  and  one  of  gravity  34  contains  143,988 
B.Th.U.  per  U.S.  gallon.  (8J  Ib.  of  water). 

The  heavier  oil  possesses  the  greater  calorific  capacity  per 
gallon.  It  would  be  better  practice  to  sell  oil  by  weight  or  to 
state  calorific  capacities  per  gallon.  For  marine  work  the  best 
oil  contains  the  greatest  heat-producing  capacity  per  unit  of 
volume,  for  this  implies  so  much  more  efficiency  of  bunker 
capacity. 

Approximately  the  two  extreme  oils  named  contain  per 
imperial  gallon  (of  10  Ib.  water) — 

Gravity  23°B  =  181,340  B.Th.U. 
34°B  =  172,870  B.Th.U. 


THE   ECONOMIES   OF  LIQUID  FUEL  45 

An  average  oil  measures  about  one  million  B.Th.U.  per  cubic 
foot,  or  35,000,000  units  per  35  cubic  feet  of  space.  A  ton  of 
coal  which  occupies  about  35  cubic  feet  contains  about  33,000,000 
units  of  heat.  In  heat  capacity,  oil  has  the  advantage  over 
coal,  apart  from  the  fact  that  oil  can  be  stored  in  small  ballast 
tanks,  and  the  coal  bunker  capacity  of  a  ship  can  then  be  used 
for  paying  cargo.  / 

Texas  and  California  Oils. 

These  oils  are  used  as  they  are  found,  that  is  to  say,  princi- 
pally in  crude  form. 

Determinations  have  been  made  of  the  calorific  effect  of  these, 
and  two  are  subjoined — 


B.Th.U. 

Calories. 

Lucas  Well-  Jefferson  Co  
Higgins  Oil  &  Fuel  Co.  —  Jefferson  Co.         . 

19,574 
19,785 

10,874 
10,992 

Texas  oil  is  high  in  sulphur,  containing  this  to  the  extent  of 
2  per  cent.  It  is  said  that  no  injurious  effects  are  produced  upon 
fire-boxes  or  boiler-plates  generally,  and  it  appears  rational 
that  this  should  be  so.  The  furnace  products  never  pass  away 
except  at  a  temperature  above  that  of  saturated  steam,  and 
it  appears  unlikely  that  the  dry  hot  furnace  gases  should  con- 
dense to  moisture  on  the  boiler-plates,  especially  of  highly 
heated  high  pressure  boilers.  Care  is  of  course  always  neces- 
sary that  furnace  gases  shall  not  make  contact  with  any  surface 
water  cooled  below  100°  F.  —  38°C.  Otherwise  corrosion  may 
occur.  Dry  sulphur  oxides,  however,  seem  to  be  innocuous. 

The  Tables  I,  II,  III,  and  IV  are  given  by  Sir  Boverton 
Redwood,  whose  works  may  be  consulted  in  all  that  relates  to 
the  chemistry  of  petroleum,  which  is  too  wide  a  subject  fully  to 
be  dealt  with  here. 

Six  thousand  heat  units  are,  states  Dr.  Engler,  rendered 
latent  in  liquefying  carbon,  but  this  appears  doubtful,  for  the 
conversion  of  solid  carbon  into  gaseous  carbon  is  not  proved 
to  render  latent  more  than  5,817  B.Th.U.  per  pound,  though 
Berthelot  states  that  there  may  be  a  further  amount,  which  he 
denotes  as  e.  It  is  improbable  that  the  liquid  form  of  carbon 
will  absorb  so  much  as  6,000  units.  As  regards  water,  tfre 
latent  heat  of  liquid  is  only  about  one-seventh  the  latent  heat 
of  vaporization.  It  is  probable  that  a  considerable  difference 
exists  also  in  the  case  of  carbon.  Against  this  is  to  be  placed 


46  LIQUID  FUEL  AND  ITS  APPARATUS 

the  fact  that  carbon  has  no  intermediate  state  between  solid 
and  gaseous,  but  passes  directly  from  one  to  the  other  when 
burned.  It  can  only  be  said  to  be  liquid  when  combined  with 
other  elements. 

Russian  Petroleum. 

Russian  oils  are  the  inverse  of  the  American  oils,  for  while 
the  latter  contain  about  25  per  cent,  of  residuum,  the  former 
may  contain  75  per  cent.  Astatki  or  residuum  varies  from 
35  to  60  per  cent,  of  the  crude  oil,  and  is  really  the  chief  product 
of  the  Russian  oils. 

The  specific  gravity  of  crude  petroleum  varies  from  0-771  to 
1-020,  and  the  following  general  values  are  given  by  Sir  Boverton 
Redwood. 

Sp.     Gr. 

Crude  petroleum  (Redwood)  ....  0-771  to   1-020 

American  (Hofer) 0-785  to  0-936 

Wyoming  ' 0-945 

Galician 0-799  to  0-902 

Baku 0-854  to  0-899 

Canada 0-859  to  0-877 

The  percentage  of  residue  in  various  oils  is  given  as  follows — 

Pennsylvania 5  to  10% 

Galician 30  to  40% 

Roumanian 25  to  35% 

Alsace 35  to  60% 

Baku 36  to  60% 

The  composition  of  oils  is  thus  very  varied. 

Creosote  Oils. 

Properly  speaking,  creosote  is  that  distillate  from  coal  tar 
which  is  intermediate  between  crude  naphtha  and  pitch. 

It  is  sometimes  called  dead  oil  and  heavy  oil,  because  its 
specific  gravity  is  greater  than  unity. 

In  a  wider  sense  creosote  oil  is  understood  to  include  the 
heavier  oils  from  bituminous  shales  as  well  as  the  liquid  de- 
posited from  coke  oven  and  blast  furnace  gases.  These  various 
oils  are  all  combustible,  and  though  by  no  means  properly 
called  creosote,  the  distinction  is  not  of  importance  as  regards 
their  value  as  fuel. 

True  creosote  is  probably  too  valuable  as  an  antiseptic  in 
wood  preservation  to  allow  of  its  very  extensive  use  as  fuel. 

Coal  tar  creosote  consists  of  that  part  of  the  tar  which  distils 
between  200°C.  and  300°C.,  and  includes  various  naphthalene 
bodies,  etc.  In  colour  it  is  yellow  green  and  fluorescent.  Its 
specific  gravity  is  1*10  to  1-024,  according  to  quality,  the 


THE   ECONOMIES   OF  LIQUID  FUEL 


47 


London  made  oils  being  heavier  than  provincial  oils,  simply 
because  London  is  supplied  largely  with  Newcastle  coal,  while 
country  oils  are  from  Midland  coals  of  different  quality. 

As  regards  the  constituents  of  creosote,  the  chief  are  naphtha- 
lene, carbolic  acid  and  cresylic  acid,  and  the  composition  of 
these  bodies  is  as  follows — 

Creosote. 


Constituent. 

Formula. 

Percentage  composition. 

Carbon. 

Hydrogen. 

Sp.  Gr. 

Melting 
Point. 

Naphthalene 
Carbolic  acid 
Cresylic  acid 

GIO^S 
C6H60 
C7H80 

93-75 
76-5 

77-78 

6-25 
6-3 
7-4 

0-978 
1-056 
1-04 

79°C. 
42°C. 
33°C. 

The  foregoing  is  a  very  brief  summary  of  the  properties  oi 
creosote  oils.  Full  information  is  to  be  found  as  regards  the 
chemistry  of  the  coal  tar  compounds,  in  vol.  ii.  of  Allen's 
Commercial  Organic  Analysis.  The  above  will  serve  to  show 
that  these  tar  products  are  largely  combustible,  and  may  be 
burned  in  the  same  way  and  with  the  same  apparatus  as  used 
for  petroleum. 

The  fuel  oil  of  the  Anglo-American  Co.  is  crude  oil  deprived 
of  its  more  volatile  constituents.  Its  specific  gravity  is  0-893 
to  0-910  at  60°F.,  and  the  closed  test  flash  point  is  220°  to 
250°C.,and  the  calorific  value  19,000  to  19,800  B.Th.U.  per  Ib. 

Blast  furnace  oil  has  a  specific  gravity  of  0-988  ;  shale  oil 
creosote  is  similar.  Coal  tar  from  gas  works  has  a  specific 
gravity  of  140  to  1-20,  and  is  very  complex  in  composition. 
London  tar  contains  from  2-5  to  8  per  cent,  of  ammoniacal 
liquor,  0'5  to  3-4  per  cent,  of  light  oils,  17  to  23  per  cent,  of 
creosote  and  carbolic  oils,  13  to  17  per  cent,  of  anthracene  oils, 
and  58  to  62  per  cent,  of  pitch. 

The  distillates  from  coal,  bituminous  shale  and  wood  all 
contain  more  or  less  oxygenated  bodies.  Coal  and  shale  dis- 
tillates contain  some  nitrogenized  bodies.  Petroleum,  on  the 
other  hand,  contains  only  hydrocarbons. 

Shale  tar  has  a  specific  gravity  of  0-865  to  0-894  according  to 
the  method  of  retorting  practised.  It  consists  of  a  complex 
mixture  of  hydrocarbons  of  the  paraffin  order  CnH2n+2  ;  of 
the  olefin  order  CnH2n,  and  of  hydrocarbons  CnH2n_2  with 
some  oxygenated  bodies. 

About  thirty  gallons  of  oil  can  be  distilled  from  each  ton  of 
shale. 


CHAPTER  III 

THE  CHEMISTRY  OF  TEXAS  PETROLEUM 

IN  Bulletin  No.  4  the  Chemical  Laboratory  of  the  University 
of  Texas,  Dr.  E.  Everhart  gave  the  results  of  an  examin- 
ation of  the  Nacogdoches  oil,  the  analysis  having  been  made 
by  Mr.  P.  H.  Fitzhugh.  The  report  says — 

"  The  oil  has  a  brownish-red  colour.  The  odour  is  peculiar, 
but  not  so  offensive  as  the  crude  petroleum  of  Pennsylvania. 
At  ordinary  temperature  the  oil  is  mobile,  but  not  so  much  so 
as  ordinary  petroleum.  Submitted  to  extreme  cold,  the  oil 
still  retains  its  liquidity,  but  becomes  less  mobile.  The  tempera- 
ture of  the  oil  was  reduced  to  less  than  zero  (Fahrenheit) 
without  it  losing  its  flowing  qualities. 

"  At  no  temperature  attainable  in  the  laboratory  by  artificial 
means  could  any  solid  paraffin  be  separated.  The  oil  does  not 
gum  on  exposure  to  the  air.  It  is  not  adapted  to  the  produc- 
tion of  illuminating  oil ;  its  value  consists  in  its  use  as  a 
lubricant. 

"  About  four  pounds  of  oil  was  subjected  to  distillation  over 
the  naked  flame  in  a  retort  connected  with  proper  condensers. 
The  temperature  was  carried  up  to  680°F.  At  intervals  of 
45°  each  distillate  was  removed  and  its  weight  determined. 
The  results  of  the  distillation  were  as  follows— 

Analysis  of  Nacogdoches  Oil. 

Per  cent,  by  weight. 

Below  300°F 0-04 

300°  to  345°F .      .      .      .  0-37 

345°  to  390°F a  1-38 

435°  to  480°F 3-14 

480°  to  525°F 6-25 

525°  to  615°F .  7-07 

615°  to  680°F 5-63 

Remaining  in  the  retort 74-03 

"  The  above  figures  show  that  the  crude  petroleum  is  practi- 

48 


THE   CHEMISTRY   OF  TEXAS   PETROLEUM      49 

cally  free  from  naphtha,  which  distils  off  below  250°F.  Four 
pounds  of  this  oil  carried  to  a  temperature  50°  higher  yielded 
only  a  few  drops  of  a  light  oil,  amounting  to  0-04  per  cent,  of 
the  total  amount  taken.  In  the  Pennsylvania  crude  petroleum 
the  illuminating  oil  comes  off  between  250°  and  500°F.,  and, 
on  an  average,  amounts  to  about  55  per  cent.  The  Nacog- 
doches  petroleum  between  the  same  degrees  of  temperature 
yields  only  a  little  over  7  per  cent.  Three-fourths  of  the  oil 
does  not  boil  until  a  temperature  above  the  boiling  point  of 
mercury  is  reached.  Above  400°F.  and  even  lower  the  dis- 
tillate is  not  pure  white,  but  is  somewhat  coloured.  This 
colour  deepens  on  exposure  to  the  atmosphere.  The  distillate 
exhibits  fluorescence. 

"  The  density  at  62-6°F.  is  0-9179.  That  of  Pennsylvania  oil 
is  usually  about  0-794  to  0-840.  The  co-efficient  of  expansion 
is  0:02568." 


Properties  of  Petroleum. 

W.  B.  Phillips,  Ph.D.,  of  the  University  of  Texas,  says — 

"  In  weight  (specific  gravity),  taking  water  as  1,000,  it  varies 
from  650,  as  in  certain  oils  from  Koudako,  Russia,  to  1,020, 
as  in  the  oil  from  the  island  of  Zante.  The  range  is,  however, 
for  the  most  part,  between  770  and  940.  A  gallon  of  crude 
petroleum  will  vary  from  6-41  pounds  to  7-83  pounds  for  the 
United  States  gallon,  and  from  7»20  to  9 -40  pounds  for  the 
Imperial  gallon.  Exclusive  of  the  barrel,  the  40  gallons,  or- 
dinarily spoken  of  as  a  barrel  of  oil,  will  weigh  from  269-22 
pounds  to  328-86  pounds. 

"With  regard  to  its  flow,  crude  petroleum  may  be  quite  mobile, 
as  in  the  light-coloured  varieties,  or  quite  viscid,  as  in  the  black 
varieties.  The  temperature  at  which  it  becomes  solid  ranges 
from  82°F.,  as  in  oil  from  Burma,  to  several  degrees  below  zero. 
The  flash-point  (the  lowest  temperature  at  which  inflammable 
vapours  are  given  off)  varies  from  below  zero,  in  certain  oils 
from  Italy,  Sumatra,  etc.,  to  370°F.  in  oils  from  the  Gold  Coast, 
Africa.  The  ordinary  range  of  the  flash-point,  however,  does 
not  show  such  extreme  limits." 

For  oils  whose  flash-point  lies  below  60°F.  the  specific 
gravity  ranges  from  771  to  899,  the  average  being  838.  On 
the  other  hand,  the  oils  whose  flash-points  are  above  the  boiling- 
point  of  water  have  a  range  of  specific  gravity  from  921  to  1,000, 
the  average  being  959.  It  is  remarkable  that  a  Roumanian  oil 
with  a  flash-point  of  24°F.  should  have  had  a  specific  gravity 

D 


50  LIQUID  FUEL  AND  ITS   APPARATUS 

of  899.  As  a  general  rule  low  specific  gravity  accompanies  a  low 
flash-point.  In  none  of  the  examples  examined,  whose  flash 
point  was  above  the  boiling-point  of  water,  did  the  specific  gravity 
fall  below  921,  the  average  being  959.  There  is  a  close  con- 
nection between  specific  gravity  and  flash-point,  for  the  presence 
of  lighter  oils,  which  are  given  off  at  a  low  temperature  and  are 
more  inflammable,  tends  to  reduce  the  weight  of  the  oil  as 
compared  with  water.  This  is  not  always  so. 

The  boiling-point  of  crude  petroleum  varies  from  180°F. 
with  certain  Pennsylvania  oils,  to  338°F.  with  oil  from  Hanover, 
Germany.  The  point  at  which  oils  become  solid  varies  from 
82°F.  with  oil  from  Burma,  to  below  zero  with  oil  from  Italy 
and  Sumatra. 

The  content  of  carbon  varies  from  79-5  per  cent,  to  88-7 
per  cent.  ;  of  hydrogen  from  9-6  per  cent,  to  14-8  per  cent. ;  of 
sulphur  from  O07  per  cent,  to  above  2-00  per  cent.,  and  in  rare 
cases  even  above  3-00  per  cent. ;  of  nitrogen  from  0-008  per  cent., 
to  I'lO  per  cent. 

Hydrocarbons  of  the  olefin  series  occur  in  nearly  all  kinds  of 
petroleum,  but  are  specially  characteristic  of  Russian  petroleum 
from  Baku. 

Mabery  has  shown  that  the  distillate  from  Beaumont  oil 
coming  over  between  266°  and  275°F.,  gave  hydrocarbons  of  the 
acetylene  and  benzine  series,  and  the  same  was  true  of  the 
distillate  coming  over  between  311°  and  320°F.  He  also  found 
this  oil  to  contain  2-16  per  cent,  of  sulphur  and  more  than 
1-00  per  cent,  of  nitrogen. 

There  is  no  hard  and  fast  line  of  demarcation.  The  chemical 
properties  shade  into  each  other,  and  only  a  general  statement 
can  be  made  that  the  oils  from  Pennsylvania  fall  into  the 
paraffin  series  and  the  Russian  into  the  olefin  series,  while 
the  Beaumont  oil  is  a  third  class  distinguished  by  the  presence 
of  members  of  the  acetylene  and  benzine  groups. 

Bituminous  coal  contains  much  less  carbon  and  hydrogen 
and  much  more  oxygen  than  petroleum.  Anthracite  coal 
has  about  the  same  amount  of  carbon  as  petroleum,  but  much 
less  hydrogen  and  oxygen. 


THE   CHEMISTRY  OF  TEXAS   PETROLEUM      51 


Mr.   E.  H.   Earnshaw   made   an   analysis    of    Corsicana   oil, 

as  follows: — 

Analysis  of  Petroleum  from  Corsicana,  Texas. 


Fractions. 

Temperature, 
F. 

Per  cent. 

Sp.  Gr.  at 
60°F. 

By  Vol. 

By 

Weight. 

Colourless 
A     

130°-200° 
200°-250° 
250°-300° 
300°-350° 
350°-400° 
400°-450° 
450°-500° 

500°-550° 
550°-600° 
600°-650° 
650°-665° 
650° 
650° 

2-80 
5-10 
7-60 
8-20 
9-40 
7-40 
8-30 

6-45 
7-75 
14-95 
17-25 
1-30 
1-40 
2-63 

2-24 
4-31 

6-69 
7-44 

8-75 
7-07 
8-09 

6-43 
7-85 
15-43 
18-07 
1-41 
1-63 

0-6653 
0-7017 
0-7302 
0-7527 
0-7718 
0-7920 
0-8088 

0-8260 
0-8404 
0-8555 

0-8687 
0-8972 
0-9669 

B           

c   

D    

E           

F     

G     

Very  faint  yellow 
H    

I     

Yellow,  J     

Deep  reddish  yellow,  K    . 
Deep  red  (solid),  L,  over  . 
Dark  red-brown  (solid),  M,  over 
Residue        

Total    . 

97-90 

98-04 

Mr.  Thiele's  remarks  on  the  oil  were  as  follows — 

"  The  oil  is  very  dark  brown  and  opaque,  but  thin  and  fluid 
at  60°F.  The  specific  gravity  at  60°F.  is  0-8292.  The  oil  is 
closely  related  to  the  oil  from  Washington  district,  Penn.,  but 
contains  asphaltum  or  bodies  similar  to  it. 

"  Nacogdoches  oil  is  heavy,  specific  gravity  0*915.  The 
colour  is  black,  and  there  is  much  sulphuretted  hydrogen. 

"  Oil  from  Saratoga,  Hardin  county,  is  heavier,  the  specific 
gravity  being  0-995.  It  is  black  and  rich  in  asphaltum. 

"  Oil  from  Sour  Lake,  Hardin  county,  has  a  specific  gravity 
of  0-963,  and  analyses  as  follows — 

Analysis  of  Petroleum  from  Sour  Lake,  Hardin  County,  Texas. 


Fractions. 

Temperature 
F. 

Per  cent, 
by  Vol. 

Specific 
Gravity. 

Colour, 

etc. 

1 

2 

212°-266° 

0=07 

Yellow 

3 

266°-320° 

0-03 

Yellow 

4 

320°-  392° 

1-59- 

0-684 

Yellow 

5 

392°-572° 

19-49 

0-840 

Yellow  ;  blue 

fluorescence 

6 

7 

572°-641° 

5-15 

0-782 

Dark  yellow 

Residue    . 

71-11 

0-978 

Black 

Total    . 

97-44 

52  LIQUID  FUEL  AND  ITS  APPARATUS 

In  the  Journal  of  the  Society  of  Chemical  Industry,  vol.  xix., 
No.  2,  February  28,  1900,  Mr.  Clifford  Richardson  has  the 
following — 

Corsicana  Oil. 

Specific  gravity,  68°F.       .      .      .        0-8457 

Baume 35-6  (about) 

Flash Ordinary  temperature. 

Volatile,  212°F 10-8  per  cent,  (naphtha). 

Volatile  324°F.,  7  hours     .      .      .  35-7 

Volatile  339°F.,  5  hours      .      .      .  11-2 

Total 57-7 

Residue,  after  heating  to  323°F.,  flows  readily  at  68°F., 
appears  to  contain  paraffin.  After  heating  to  399°F.  residue 
has  a  quick  flow  at  77°F. 


Sour  Lake  Oil. 

Specific  gravity,  68°F.       .      .      .        0-9458 

Baume   .  18-0 

Flash 244°F. 

Volatile,  212°F 22-8  (water  with  trace  of  oil) 

Volatile,  324°F.,  7  hours  .       .      .  12-6 

Volatile,  399°F.,  5  hours  .       .      .  14-4 


Total 49-8 

Residue  after  heating  to  324°F.  flows  readily  at  70°F.  After 
heating  to  399°F.?  residue  flows  readily  at  77°F. 

The  specific  gravity  of  Corsicana  petroleum  is  a  little  greater 
than  that  from  near  Dudley,  Noble  county,  Ohio,  0*8457  to 
0-8333. 

Distilled  under  ordinary  pressure,  without  particular  pre- 
cautions to  prevent  cracking,  Mr.  Thiele  found — 

Sp.  Gr. 

Naphtha,  10-8  per  cent 0-710 

Kerosene,  54-5  per  cent.    . 0-796 

Residue,  34-7  per  cent 0-905 

Twenty  grams  of  the  oil,  heated  for  seven  hours  in  an  air 
bath  at  various  temperatures  in  a  crystallizing  dish  2|  inches 
in  diameter  by  1|  inches  high,  left  a  residue  of  43-3  per  cent., 
which  flowed  readily  at  77°F.  The  residuum  resembles  that 
from  Pennsylvania  and  Ohio  petroleum,  and  apparently  con- 
tains paraffin  scale.  It  is  to  a  certain  extent  asphaltic.  The 
crude,  when  distilled  under  a  pressure  of  1  inch  of  mercury, 
volatilized  51-2  per  cent,  at  a  temperature  of  356°F.,  but  began 
to  "  crack."  Ohio  oil  did  not  begin  to  "  crack  "  until  455°F. 


THE  CHEMISTRY  OF  TEXAS   PETROLEUM      53 


at  atmospheric  pressure  ;  but  the  Sour  Lake  oil  broke  up  at  the 
same  point  as  did  the  Corsicana.  It  is,  therefore,  a  less  stable 
oil  than  eastern  petroleums. 

The  Sour  Lake  oil  is  a  very  heavy  crude  petroleum,  18B, 
and  corresponds  in  many  respects  with  some  of  the  heavier 
California  oils  of  Summerland  and  Los  Angeles  in  appearance 
and  properties.  It  flashes  at  a  low  point  for  such  a  heavy 
oil,  244°F. 

Properties  of  various  Petroleums. 

The  following  table  is  taken  from  Sadtler's  Industrial  Organic 
Chemistry — - 


Crude  Oil  from 

Sp.  Gr.  at 
63°F. 

Began 
to  boil 
at  °F. 

Under 
302°F. 
per  cent. 

302°  to  572° 
per  cent. 

Over  581° 
per  cent. 

Texas-Corsicana 

0-821 

176 

34-6 

40-0 

15-8 

Pennsylvania 
Galicia     . 

0-818 
0-824 

180 
194 

21-0 
26-5 

38-0 
47-0 

40-7 
26-5 

Baku       .      . 

0-859 

196 

23-0 

38-0 

39-0 

Alsace 

0-907 

275 

33-0 

50-0 

47-0 

Hanover  . 

0-899 

238 

32-0 

68-0 

Dr.  W.  H.  Harper,  Professor  of  Chemistry  in  the  University 
of  Texas,  gives  an  analysis  of  a  sample  of  Corsicana  oil — 

Colour,  very  dark  brown,  almost  black  ;  opaque  except  in 
thin  layers  ;  greenish  fluorescence. 

Viscosity,  not  determined,  but  the  oil  very  mobile  at  32°  F. 

Sediment,  none. 

Water,  none. 

Flash-point,  73°F. 

Specific  gravity  at  63-5°F.,  0-8586,  equivalent  to  33°  Baume. 

Calorific  Capacity  of  Petroleum. 

The  B.Th.U.  in  petroleum  vary  from  17,000  to  20,000,  one 
experiment  giving  20,110.  The  value  taken  in  Texas  is 
18,500  B.Th.U.,  or  10,277  calories.  The  scientific  investiga- 
tion of  the  coals,  etc.,  used  there,  with  respect  to  their  heat 
units,  has  not  progressed  very  far  ;  but  if  is  not  thought  that, 
on  the  average,  the  B.Th.U.  in  the  coals  will  be  above  12,600, 
if  indeed  above  10,800,  and  are  taken,  for  the  present,  at  11,700. 
For  the  lignites  a  lower  value  must  be  taken,  and  for  the  present 
this  will  be  9,900. 

Some  of    the  Alabama  coals  have   13,500  B.Th.U.  ;    good 


54  LIQUID  FUEL  AND  ITS  APPARATUS 

McAlester  coal  (Indian  Territory)  may  be  taken  at  the  same  ; 
New  Mexico  coal  at  12,000  ;  and  lignite  at  9,900.  On  this  basis 
one  barrel  of  crude  petroleum,  weighing  320  Ib.  net.  would  be 
equivalent  to  438  Ib.  of  Alabama  coal,  and  the  same  amount 
of  McAlester  coal,  493  Ib.  of  New  Mexico  coal,  and  598  Ib.  of 
lignite.  A  ton,  2,000  Ib.,  of  Alabama  coal  would  then  be 
equivalent  to  4-56  barrels  of  petroleum  ;  a  ton  of  McAlester 
coal  to  4-56  barrels  ;  a  ton  of  New  Mexico  coal  to  4-06  barrels  ; 
and  a  ton  of  lignite  to  3-34  barrels.  In  other  words,  from 
3J  to  4J  barrels  contain  as  many  heat  units  as  a  ton  of  the  best 
coals  and  lignites  of  American  Southern  States. 

Experiments  made  in  California  with  a  view  to  testing  the 
relative  value  of  the  California  oil  and  the  coal  with  which  it 
comes  into  competition,  showed  that  a  ton  of  Nanaimo  coal, 
giving  12,031  B.Th.U.,  was  equivalent  to  a  minimum  oil 
consumption  of  3*45  barrels  and  a  maximum  consumption  of 
3-87  barrels.  Experiments  on  Texas  petroleum  showed  it  to 
have  19,160  heat  units,  and  this  would  be  equivalent  to  4*29 
barrels  per  ton  of  Indian  Territory  coal.  In  Russia  the  usual 
equivalent  is  3»12  barrels  per  ton  of  coal. 

There  is  considerable  variation  in  the  quality  of  coal,  and 
these  differences  are  often  observable  in  coal  from  the  mine, 
due,  perhaps,  to  carelessness  in  mining  and  handling,  and  to  the 
absence  of  rigid  inspection.  In  countries  where  coal  is  sold 
on  the  basis  of  heat  units  these  discrepancies  are  less.  Varia- 
tions in  the  quality  of  oil  from  the  same  well  are  by  no  means 
so  marked  as  in  the  case  of  coal  from  the  same  mine.  The 
practice  of  piping  different  oil  into  the  same  storage  tanks 
tends  to  advance  uniformity. 

The  value  of  oil  as  compared  with  coal  varies  with  the  nature 
of  the  work  to  be  done.  It  has  been  observed  that  in  puddling 
and  steel-heating  furnaces  2|  barrels  of  Los  Angeles  oil  were 
equivalent  to  2,000  pounds  of  Wellington  coal  from  British 
Columbia,  while  for  steaming  purposes  it  took  three  barrels  of 
the  oil  for  one  ton  of  the  coal.  In  some  establishments  in  Los 
Angeles  the  proportion  rose  to  3-62  barrels  per  ton  ;  in  others, 
to  3-10.  On  the  Southern  Pacific  Railway  it  has  been  found 
that  four  barrels  of  California  oil  were  equivalent  to  one  ton 
of  Nanaimo,  British  Columbia,  coal.  The  lowest  consumption  of 
oil  per  ton  of  coal  that  has  been  found  is  2J  barrels,  while  the 
highest  is  4  barrels,  t  In  a  general  way,  from  3|  to  4  barrels  of  oil 
should  be  equivalent  to  a  ton  (2,000  pounds)  of  good  soft  coal. 
The  lower  figures  may  be  reduced  under  good  practice  and 
management  and  the  best  appliances  to  3  J  barrels  ;  while  under 
bad  management,  etc.,  the  higher  figure  may  reach  4J  barrels.  / 


THE  CHEMISTRY  OF  TEXAS  PETROLEUM      55 

Advantages  of  Liquid  Fuels. 
The  advantages  to  be  derived  from  the  use  of  liquid  fuel  are — 

1.  Diminished  loss  of  heat  up  the  funnel  (or  chimney),  owing 
to  the  clean  condition  in  which  the  boiler  tubes  can  be  kept, 
and  to  the  smaller  amount  of  air  which  has  to  pass  through  the 
combustion-chamber  for  a  given  fuel  consumption. 

2.  A  more  equal  distribution  of  heat  in  the  combustion- 
chamber,  as  the  doors  do  not  have  to  be  opened,  and  a  higher 
efficiency  is  obtained  ;  unequal  strains  on  the  boiler  tubes,  etc., 
due  to  undue  heating,  are  also  avoided. 

3.  No  danger  of  having  dirty  fires  on  a  hard  run. 

4.  A  reduction  in  the  cost  of  handling  fuel. 

5.  No  firing  tools  or  grate-bars  are  necessary  ;  consequently 
the  furnace  lining,  brickwork,  etc.,  last  longer. 

6.  Absence  of  dust,  ashes  and  clinkers. 

'  7.  Petroleum  does  not  deteriorate  on  storing,  while  coal  does, 
especially  soft  coal.     This  opinion  is  not  universal,  however. 

8.  Ease  with  which  the  fire  can  be  regulated  from  a  low  to  a 
most  intense  heat  in  a  short  time. 

9.  Lessening  of  the  amount  of  manual  labour  in  stoking. 

10.  Great  increase  of  steaming  capacity,  the  difference  being 
as  much  as  35  per  cent,  in  favour  of  oil. 

11.  The  absence  of  sulphur  or  other  impurities,  and  longer 
life  to  plates,  etc.  ;  but  considering  the  fact  that  the  amount 
of  sulphur  in  some  of  the  oils  now  being  used  as  fuel  is  in  excess 
of  the  sulphur  in  ordinary  coals,  this  point  is  not  well  taken. 
Sulphur  is  objectionable  in  any  fuel,  whether  coal  or  oil,  and 
of  the  two  may  be  more  objectionable  in  oil  than  in  coal,  for  a 
portion  of  the  sulphur  in  coal  remains  in  the  ashes,  and  is  not 
consumed. 

If  crude  petroleum,  or  the  residue  from  refining  plants,  is  to 
come  into  use  on  a  large  scale  as  fuel,  there  are  some  consider- 
ations that  must  be  weighed,  in  addition  to  its  fuel  value,  viz., 
its  initial  price,  f.o.b.  tanks  or  wells,  transportation  charges, 
and  the  like. 

Profiting  by  the  experiences  in  California  and  elsewhere  in  the 
use  of  oil  for  fuel,  many  industrial  establishments  in  Texas 
changed  from  coal  to  oil.  Among  the  first  was  the  American 
Brewery,  Houston,  with  two  200  h.p.  and  two  350  h.p. 
boilers.  The  oil  was  the  residue  from  the  refining  plant  at 
Corsicana-,  and  it  was  estimated  that  75  barrels  a  day  would 
be  required,  as  the  coal  consumption  was  about  25  tons  a  day. 
After  running  for  a  while,  it  was  stated  that  the  steaming 
capacity  of  the  two  200  h.p.  boilers  using  oil  was  equivalent 


56  LIQUID  FUEL  AND  ITS  APPARATUS 

to  that  of  the  two  350  h.p.  boilers  using  coal,  and  the  saving 
of  oil  was  about  33  per  cent.  The  Star  Flour  Mills,  Galveston, 
installed  oil  burners  in  April,  1901,  using  about  35  barrels  a 
day  for  a  350  h.p.  engine. 

The  first  locomotive  equipped  for  burning  oil  was  delivered 
to  the  Gulf,  Beaumont  and  Kansas  City  Railway,  June  20, 
1901,  and  belonged  to  the  Gulf,  Colorado  and  Santa  Fe  Railway. 
Up  to  the  time  of  its  reaching  Beaumont  it  had  travelled  450 
miles,  and  consumed  42  barrels  of  oil,  the  tank  having  this 
capacity.  The  Southern  Pacific  Railway  burns  oil  west  of  El 
Paso. 

TESTS  OF  TEXAS  OIL  EFFICIENCY. 

A  report  by  Professor  Denton  states  that  the  number  of 
barrels  of  oil  equivalent  to  2,240  pounds  of  coal  was  4-23  for 
one  h.p.  per  about  twenty  square  feet  of  heating  surf  ace,  and 
4-12  for  one  h.p.  per  10  square  feet  of  heating  surface  ;  and  it 
appears  that  the  average  consumption  of  oil  per  ton  of  coal  is 
four  barrels,  and  that  under  some  conditions  this  falls  to  3-50 
barrels.  There  may  be  consumers  who  use  even  less  than  this, 
but  it  is  not  thought  that  they  represent  the  average  practice. 

Beaumont  oil  was  used  to  operate  a  boiler  at  the  plant  of  the 
West  Side  Hygeia  Ice  Company,  West  19th  Street,  N.Y.  City. 
There  were  three  return  tubular  boilers,  each  6  feet  in  diameter 
and  18  feet  long,  containing  about  1,900  square  feet  of  heating 
surface,  two  being  used  at  a  time  to  provide  about  180  boiler 
h.p.  from  buckwheat  coal,  with  natural  draught  under  a  very 
steady  load  throughout  each  24  hours.  One  of  these  boilers 
was  fitted  for  the  tests  with  the  Williams  Oil  Burner. 

Effect  of  the  Oil  on  the  Boiler  and  Furnace. 

After  the  steam-raising  test,  the  boiler  was  operated  24  hours 
with  oil,  to  use  up  all  that  remain  of  the  117  barrels  provided 
for  the  evaporative  test.  It  was  then  cooled,  and  the  oil- burning 
apparatus  removed  to  prepare  the  furnace  for  coal  tests.  The 
boiler  and  furnace  were  then  examined.  No  trace  was  found 
of  any  action  of  the  oil  on  the  boiler.  There  was  no  oily  matter 
on  the  internal  brickwork,  nor  any  discolouration  of  the  latter, 
and  there  was  less  than  eV  of  an  inch  of  soot  in  the  tubes, 
which  had  been  swept  clear  of  ashes  at  the  beginning  of  the 
use  of  the  oil. 

The  tests  with  oil  were  made  at  from  112  h.p.  to  220  h.p. 
The  boiler  was  6  feet  in  diameter  and  18  feet  long  of  the  hori- 
zontal return  tube  type.  It  had  100  tubes  2  J  inches  in  diameter, 


THE   CHEMISTRY  OF  TEXAS  PETROLEUM      57 


and  a  grate  surface  of  45-5  square  feet,  i.e.  6  feet  6  inches  by 
7  feet  0  inches.  Height  of  chimney,  70  feet  high  by  42  inches 
square.  The  resume  of  the  tests  is  as  follows— 

Resume  of  Tests  with  Leaumont  Crude  Oil. 


Duration,  hours  .... 
Horse  power  

3-5 

146-9 

8 
122-7 

11 

189-7 

13 

138-0 

11 

220-1 

Steam  pressure  (gauge),  Ib.  . 
Feed  temperature,  degs.  F. 
Chimney  temperature,  degs. 
F  

87 
69° 

374° 

86 
90° 

360° 

86 

70° 

398° 

86 
90° 

370° 

86 

74° 

425° 

Quality  of  steam. 
Oil  per  hour  per  sq.  ft.  of 
heating  surface,  Ib. 
Dry  steam  per  hour,  from 
and  at  212°  per  sq.  ft.  of 
heating  surface,  Ib. 
Heating  surface  perh.p.,  sq. 
ft 

dry 
0-181 

2-73 
12-6 

dry 
0-135 

2-09 
16-5 

dry 
0-226 

3-52 

9-8 

dry 
0-063 

2-56 
13-5 

dry 
0-263 

4-08 
8-45 

Total  dry  steam  per  Ib.  of 
fuel  as  fired  from  and  at 
212°F.,  Ib  
Per  cent,  of  steam  used  by 
burner  ... 

15-29 

3-6% 

15-53 

3-1% 

15-55 

4-8% 

15-71 

3-5% 

15-49 

4-8% 

Net  Ib.  of  dry  steam  per  Ib. 
of  fuel  fired  from  and  at 
212°F.    .      . 

14-74 

15-05 

14-80 

15-16 

14-75 

Other  figures  are  as  follows — 

Dimensions  and  Proportions. 

Grate  surface,  sq.  ft 45-5 

Water  heating  surface "  1,860 

Position  of  damper Wide  open 

Area  of  opening  of  ash  pits,  sq.  ft 1-8 

Average  Pressures. 

Steam  pressure,  by  gauge,  Ib 86-5 

Draught  pressure,  inches  of  water 0-37 

Average  Temperatures,  Fahr. 

Fire  room «  53-1 

Feed  water  entering  boiler 74 -C 

Chimney  gases 42-£ 

Fuel 

Weight  of  fuel  as  fired,  Ib 5,39£ 

Steam. 

Quality  of  steam dry 


68  LIQUID  FUEL  AND  ITS  APPARATUS 

Water. 

Total  weight  of  water  fed  to  boiler,  Ib 70,798 

Factor  of  evaporation 1-180 

Equivalent  water  evaporated  into  dry  steam  from  and 

at  212°F 83,542 

Economic  Results. 

Feed  water  per  Ib.  of  fuel  as  fired,  Ib 13-13 

Equivalent  evaporation  from  and  at  212°F.  per  Ib.  of 

fuel  as  fired,  Ib 15-49 

Equivalent  evaporation  from  and  at  212°F.  per  Ib.  of 

combustible,  Ib .      .      15-49 

Efficiency. 

Efficiency  of  boiler  and  furnace,  or  heat  per  Ib.  of  fuel  as 

fired,  divided  by  calorific  value  per  Ib.  of  fuel  .  78-5% 

Efficiency  of  boiler,  or  heat  absorbed  by  boiler,  per  Ib.  of 
combustible,  divided  by  calorific  value  per  Ib.  of 
combustible 78-5% 

Hourly  Quantities. 

Fuel  as  fired  per  hour,  Ib 490-3 

Fuel  as  fired  per  hour  per  sq.  foot  of  grate,  Ib.       .      .      10-78 
Combustible  per  hour  per  sq.  foot  of  heating  surface,  Ib.       0-263 

Horse  Power. 

Horse  power  at  34-5  Ib.  from  and  at  212°    .      .      .      .      220-1 
Heating  surface  per  horse  power,  sq.  feet    .      .      .      .          8-45 

Compositions  of  Fuel. 

Per  cent. 

Carbon 85-03 

Hydrogen 12-30 

Oxygen  and  nitrogen 0-92 

Sulphur 1-75 

Heat  Balance. 

B.Th.U. 

Utilized  in  production  of  steam 14,963 

Due  to  combustion  of  hydrogen 1,245 

Wasted  in  superheating  water  products       ....  113 

Wasted  in  dry  chimney  gases 1-837 

Radiation  and  imperfect  combustion 902 

Heat  per  Ib.  of  fuel  as  fired,  by  calorimeter      .      .      .  19,060 

Heat  per  Ib.  of  combustible,  by  calorimeter      .      .      .  19,060 

The  weight  of  oil  per  gallon  was  7-66  pounds,  or  322  pounds 
per  barrel  of  42  American  gallons  of  231  cubic  inches.  The  net 
evaporation,  per  pound  of  oil.  from  and  at  212°F.,  was  15-1 
pounds  ;  per  pound  of  Pennsylvania  bituminous  coal,  in  the 
best  boilers  at  10  square  feet  of  heating  surface  per  h.p.  is 
9'5  pounds  ;  of  the  semi-bituminous  coals,  such  as  Pocahontas, 


THE  CHEMISTRY  OP  TEXAS  PETROLEUM      59 

New  River,  Cumberland  and  Clearfield,  it  is  10-0  pounds,  which 
may  be  increased  to  10-5  and  11  pounds  by  mechanical  stokers, 
or  smoke-preventing  devices. 

Professor  Denton  calculates  the  comparative  costs  of  oil  and 
coal  as  follows — 


Price  of  coal  per  ton                                                        Equiv.  price  of  oil  per  barrel, 
of  2,240  Ib.                                                                                of  42  gallons. 
$1.00—4/-       #0.29  —  1  /2i 

1.50  =  6/-       •      • 
2.00  =  8/-      •      • 
2.50  =  10/-    .      . 
3.00  =  12/-    .      . 
3.50  =  14/-    .      . 

4.50  =  18/-    .      . 

• 

• 

0.43  =  1/9| 
0.56=2-4 

0.85=3/6£ 
0.99=4/1^ 
1.13=4/8| 
1.28=5/4 

These  figures  apply  to  bituminous  coals  mined  west  of  Ohio. 
In  comparison  with  small  sizes  of  anthracite,  Pittsburg  bitu- 
minous and  Maryland  and  West  Virginia  semi-bituminous  coals, 
and  most  or  all  British  coals,  oil  must  be  sold  at  a  less  price, 
inasmuch  as  these  fuels  are  of  a  better  quality  than  Western 
and  South -Western  coals. 

Evaporative  Duty. 

Professor  Denton' s  results  show  that  the  net  evaporation 
ranged  from  14-74  to  15-16  pounds  of  water  per  pound  of  oil, 
the  h.p.  varying  from  112  to  220  and  the  burner  steam  con- 
sumption from  3-1  to  4-8  per  cent,  of  the  boiler  output.  The 
boiler  utilized  about  78  per  cent,  of  the  heat  of  the  fuel,  which 
may  be  considered  the  best  average  boiler  practice.  It  is  also 
to  be  observed  that  the  results  in  actual  practice  showed  that 
98  per  cent,  of  the  total  heat  of  combustion  of  the  oil,  as  deter- 
mined by  the  calorimeter,  was  accounted  for  by  the  steam  pro- 
duction, the  chimney  gases  and  a  reasonable  allowance  for 
radiation.  Professor  Denton  thinks  that  for  a  higher  horse- 
power a  net  evaporation  of  14-8  pounds  of  water  is  the  best 
economy  that  can  be  expected  from  the  use  of  oil  as  fuel  with 
steam  jet  burners.  This  may  be  contrasted  with  11-79  pounds 
yielded  by  excellent  No.  1  buckwheat  coal. 

Considering  the  objections  that  have  been  raised  against  the 
use  of  crude  oil,  on  account  of  its  content  of  sulphur,  it  may  be 
said  that  many  excellent  steam  coals  carry  from  1  -5  to  2  per  cent 
of  sulphur,  and  that  the  average  life  of  a  boiler  does  not  seem 
to  be  impaired  by  their  use.  The  amount  of  sulphur  in  the  oil 
used  by  Professor  Denton  was  T63  per  cent.  Allowing  that  a 
coal  contains  1-7  per  cent.,  an  oil  would  have  to  contain  2-6  per 
cent,  in  order  to  put  as  much  sulphur  into  the  products  of  com- 


60 


LIQUID  FUEL  AND  ITS  APPARATUS 


bustion  as  the  coal,  equal  horse-powers  being  assumed.  It  has 
been  ascertained  that  the  use  of  coal  carrying  more  than  3 
per  cent,  of  sulphur  does  not  cause  any  greater  depreciation  of 
fire-boxes,  etc.,  than  a  coal  of  1-7  per  cent,  of  sulphur,  and  the 
sulphur  equivalent  in  oil  corresponding  to  3  per  cent,  in  coal  is 
above  6  per  cent.  The  objections  to  the  use  of  crude  oil,  based 
on  its  sulphur  content,  do  not  appear  to  be  well  founded,  in  so 
far,  at  least,  as  concerns  the  integrity  of  fire-boxes,  etc.  Pro- 
bably sulphur  products  are  only  seriously  harmful  when  cooled 
to  moisture  point. 

The  inflammability  of  crude  oil  has  been  the  subject  of  critical 
investigation.  There  was  no  inflammable  vapour  given  off 
below  142°F.  in  Professor  Denton's  experiments  ;  and  he  does 
not  think  that  a  pool  of  oil  in  a  boiler  room  would  become 
ignited  from  a  lighted  match  or  from  the  dropping  of  a  live  coal 
into  it.  It  is  also  stated  that  a  surplus  of  oil  at  the  burner  gave 
rise  merely  to  a  thick  smoke  ;  there  was  no  explosion  or  excess 
of  pressure.  / 

One  more  point  of  a  most  important  nature  was  brought  out 
by  the  test.  It  was  not  a  new  point,  for  other  tests  have  estab- 
lished the  fact,  and  it  is  well  known  to  those  who  study  the 
economies  of  fuel  consumption.  It  is  the  comparative  efficiency 
of  oil  and  coal  referred  to  the  heat  balance. 


Oil. 

Coal. 

B.Th.U. 

Per  cent. 

B.Th.U. 

Par  cent. 

Utilized  in  production  of  steam. 

14,963 

78-5 

8,636 

71-4 

Evaporation  of  moisture  in  fuel  and 

due  to  combustion  of  hydrogen    . 

1,245 

6-5 

277 

2-3 

Wasted  in  superheating  water  pro- 

ducts        

113 

0-6 

23 

0-2 

Wasted  in  dry  chimney  gases 

1,837 

9-7 

1,981 

16-4 

Wasted  in  unconsumed  carbon  in  ash 

— 

— 

768 

6-3 

Radiation  and  imperfect  combustion 

902 

4-7 

415 

3-4 

Heat  per  pound  of  fuel  as  fired,  by 

calorimeter  

19,060 

100-0 

12,100 

100-0 

Heat  per  pound  of  combustible,  by 

calorimeter  

19,060 

— 

14,680 

— 

This  table  shows  that  more  heat  units  were  given  off  by  the 
oil  than  corresponded  with  the  total  number  of  heat  units 
in  the  coal,  and  that  the  percentage  of  heat  units  used  was 
78*5  of  those  in  the  oil,  as  against  71-4  of  those  in  the  coal ; 
in  other  words  the  oil  was  more  efficient  than  coal.  The  saving 
of  the  heat  ordinarily  wasted  in  dry  chimney  gases  is  especially 
noteworthy,  for  the  oil  shows  a  waste  of  9-7  per  cent.,  as  against 


THE  CHEMISTRY  OF  TEXAS  PETROLEUM       61 

16-4  for  the  coal.  In  comparison  with  coal  yielding  12,100 
B.Th.U.  per  pound  as  fired,  and  14,680  per  pound  of  combustible, 
there  is  a  decided  economy  in  the  use  of  crude  oil  under  the 
conditions  maintained  in  this  test. 

That  returns  from  consumers  of  oil  show  a  difference  of 
43  per  cent.  (i.e.  from  3*5  to  5)  in  the  number  of  barrels  of  oil 
equivalent  to  a  ton  of  good  soft  coal,  is  evidence  that  ordinary 
experience  cannot  be  relied  on  to  afford  anything  more  than  a 
rough  approximation.  If  the  ordinary  steam  installations 
were  provided  with  smoke-preventing  devices  and  mechanical 
stokers,  it  is  very  probable  that  the  economy  in  the  use  of  oil 
would  not  be  so  pronounced. 

If  all  the  economies  possible  in  the  use  of  the  solid  fuels 
were  maintained,  the  comparison  between  these  and  oil  would 
not  be  so  strongly  in  favour  of  the  latter.  When  smoke- 
preventing  appliances  are  installed  alone  or  in  connection  with 
mechanical  stoking  more  particularly,  a  saving  of  more  than 
20  per  cent,  has  been  regularly  obtained,  with  ordinary  coals. 
It  is  to  be  doubted  whether  ordinary  practice  with  solid  fuels 
has  attained  its  maximum  economy.  Establishments  where 
great  attention  is  paid  to  all  possible  economies  in  fuel  consump- 
tion form  the  exceptions. 

We  may  allow  that  the  heat  units  in  oil  are  more  easily  avail- 
able for  steam-raising  purposes  than  the  heat  units  in  coal,  and 
that,  per  unit  of  heating  power,  we  get  better  results  from  oil 
than  from  coal.  When  we  have  once  ascertained  what  we  can 
get  from  the  oil,  we  can  calculate  the  relative  advantages  in 
the  use  of  the  two.  It  is,  after  all,  a  matter  of  cost,  and  each 
particular  installation  must  be  considered  on  its  merits. 

Mexican  Oil. 

Mexico  is  now  a  large  producer  of  oil.     Mexican  Fuel  Oil 
has  the  following  characteristics  : — 
Sp.  gr.,  about  0-95  at  60°  F. 
Flash  point,  over  150°  F.  (open). 

Viscosity,  about  1,500  sees,  at  100°  (Redwood  No.  1). 
Calorific  Value,   18,750  B.Th.U. 
Sulphur,  3-5  per  cent. 


CHAPTER    IV 

THE  CHEMICAL  AND  OTHER  PROPERTIES  OF  PETROLEUM 

IN  a  work  of  this  description  a  deep  study  of  the  chemistry 
of   liquid  fuels  is  not  necessary.     For  fuller  information 
on  petroleum  chemistry  the  works  of  Sir  Boverton  Redwood 
may  be  studied. 

Petroleum  is  a  mixture  of  a  series  of  hydrocarbons  of  the 
following  types — 

1.  CnH2n+2   Methane  Series. 

2.  CnH2n        Olefin  Series. 
3. 

4. 
5. 
6. 
7. 
8. 


-4 


_6   Benzene  Series. 


-8 

-10 

-12 


Those  named  occur  in  the  greatest  quantity  and  most  fre- 
quently. The  first  is  a  light  gas  in  the  form  CH4,  and  as  the 
values  of  n  in  each  series  grow  larger,  the  members  of  the  various 
series  become  liquid  and  finally  solid. 

Thus  of  the  first  or  Methane  series  the  first  four  are  gaseous, 
Methane,  Ethane,  Propane,  and  Butane.  Series  1  is  liquid 
when  n  =  5  to  25.  Above  n  =  25,  the  solids  begin  and  generally 
in  all  the  series  a  higher  value  of  n  implies  a  higher  boiling 
point,  and  this  rises  with  some  regularity  from  n  —  9,  by  about 
20°C.  =  36°F.  for  each  additional  carbon  atom.  Hence  the  ease 
with  which  fractional  distillation  can  be  carried  on,  the  light  oils 
(gasoline,  ect.)  distilling  off  up  to  150°C.,  the  illuminating  oils 
up  to  300°C.,  and  the  residuum  being  fuel  oil,  which  still  con- 
tains the  lubricating  oils. 

Dr.  Paul,  in  discussing  Aydon's  paper,  suggested  that  liquid 
fuel  had  an  advantage  over  solid  fuel  to  the  extent  of  6,000 
B.Th.U.  per  pound,  which  he  claimed  as  the  latent  heat  of 
liquefaction,  but  this  is  elsewhere  shown  to  be  nearer  the  latent 
heat  of  evaporation  of  carbon,  while  the  latent  heat  of  lique- 
faction is  scarcely  credited  with  more  than  5  per  cent,  extra 
calorific  power,  and,  as  pointed  out  by  Mr.  C.  E.  L.  Orde,  the 


CHEMICAL   PROPERTIES   OP  PETROLEUM       63 

Bombe  calorimeter  does  not  show  anything  like  Dr.  Paul's 
figure.  It  is  also  probable  that  when  carbon  and  hydrogen  of 
the  liquid  hydrocarbons  united,  they  produced  heat  which  more 
than  counterbalances  the  effect  of  the  latent  heat  of  liquefaction. 
Indeed,  methane  gas,  CH4,  is  known  to  produce,  when  burned, 
very  much  less  heat  than  calculation  would  appear  to  indicate. 
Acetylene,  on  the  contrary,  produces  more  heat  than  calculable, 
being  endothermic. 

Water  in  Oil. 

Fuel  oil  and  water  do  not  readily  separate.  They  do  not 
differ  much  in  specific  gravity,  and  oil  is  so  viscous  that  the 
globules  of  water  cannot  force  their  way  out  of  it.  But  oil  is 
rendered  more  liquid  by  heat ;  it  expands  more  than  water, 
and  separation  is  better  effected  by  heating  the  oil.  This  is 
best  done  locally  near  the  surface  of  the  oil  in  the  bunker,  so 
that  the  heated  oil  is  at  once  drawn  ofi  lor  use,  and  heat  is  not 
wasted  in  raising  the  temperature  of  the  whole  bunker. 

The  heat  value  of  oil  is  reduced  13-14  B.Th.U.  for  each  one 
per  cent,  of  water. 

Thus  1  pound  of  oil  worth  18,831  B.Th.U.  mixed  with  10 
per  cent,  of  water,  gives  a  mixture  the  value  of  which  per 
pound  is  (18,831  x  0-9)-  131-4  =  16,816-5  B.Th.U.,  a  differ- 
ence of  1,915-5  B.Th.U.,  or  a  loss  of  nearly  two  pounds  of 
evaporation  from  and  at  212°F.  Water  also  reduces  the  flame 
temperature,  lengthens  the  flame  and  moves  the  point  of  highest 
temperature  further  along  the  flues,  and  so  diminishes  the  values 
of  the  heating  surface.  Mr.  Orde  lays  down  the  conditions 
which  show  perfect  combustion  as  an  opaque  dazzling  white 
flame  for  six  inches  from  the  nozzle,  becoming  semi-transparent 
and  almost  violet  in  colour  at  middle  length,  shading  off  to 
red  at  the  end.  With  water  mixed  in,  the  violet  colour  does 
not  appear  (see  chapter  on  Smoke)  and  the  flame  becomes  dark 
red  and  smoke-fringed.  He  states  that  at  a  temperature  of 
140°F.  =  60°C.  it  required  seven  days  to  separate  the  water 
completely  in  a  tank  of  oil.  Hence  the  use  of  a  surface  float 
as  in  Fig.  14a. 

His  figures  for  the  calorific  value  of  various  oils,  as  found  by 
the  calorimeter,  are  as  follows,  and  show  a  practical  identity 
of  value  in  all,  as  may  be  expected  from  their  chemical  com- 
position— 

Borneo 18,831  B.Th.U. 

Texas 19,242         „ 

Caucasus 18,611         „ 

Burma 18,864         „ 


64  LIQUID  FUEL  AND  ITS  APPARATUS 

According  to  Pelouze  and  Cahours,  there  are  thirty  different 
hydrocarbons  in  petroleum,  principally  of  the  type  CnH2n+2. 
For  n  =  1  and  n  =  2  the  substance  is  a  gas.  For  n  =  3  the 
boiling  point  is  0°C.  =  32°F.  For  n  =  5  the  liquid  is  very 
volatile,  the  lightest  isolated  by  the  above  chemists  being  CsHi2, 
boiling  at  30°C.  =  77°F.  The  fuel  oils  commence  at  C8H18, 
and  go  on  to  Ci5H32,  beyond  which  C20H42  to  C28H58  are  semi- 
solid.  The  point  of  ebullition  rises  20°C.  =  36°F.  for  each 
increment  of  carbon  from  C8H]8,  which  boils  at  117°  =  242- 6°F. 
to  197°C.  =  386'6°F.  for  C12H26  ;  and  257°C  =  494'6°F. 
for  Ci5H32.  Similarly  the  specific  gravity  increases  continually, 
though  less  regularly,  than  the  boiling  point  from  C5H12,  for 
which  it  is  0-63,  to  C15H32,  for  which  it  is  0-83.  The  density 
of  the  hydrocarbon  vapours  relative  to  air  are  0-5  for  n  —  1 
to  7-5  for  n  =:  15,  or  a  growth  of  0-5  for  each  grade. 

The  Russian  oils  do  not  follow  the  same  empirical  composi- 
tion as  the  American,  but  belong  rather  to  the  ethylene  series 
CuH2n  and  the  isomers,  and  to  the  benzene  series  CJH2n_6, 
of  which  benzene  C6H6,  is  the  characteristic  member.  In 
"  cracking  "  the  oils  during  distillation  even  lower  forms  are 
found :  CnH2n_8 ;  CnH2n_10,  which  occur  in  the  residues  of 
distillation.  Water  may  exist  in  the  proportion  of  5  per  cent, 
for  Baku  oil  to  10  per  cent,  for  Borneo,  but  mineral  matter  is 
always  small,  and  ash  scarcely  exceeds  0-3  to  0-4  per  cent.,  but 
is  an  undesirable  constituent  for  an  engine,  causing  cylinder 
scoring. 

By  "  cracking," .  the  distilled  liquid  becomes  more  and  more 
stable,  and  the  final  residue  is  a  mere  coke. 

Petroleum  distils  more  easily  when  superheated  steam  is 
blown  through  the  still  while  below  the  "  cracking  "  point. 
The  effect  is  peculiar  to  steam  and  cannot  be  secured  with  air. 
It  appears  to  be  a  sort  of  solution  of  the  petroleum  by  the 
steam,  and  Mr.  Bertin,  of  the  French  Marine  Militaire,  con- 
siders that  this  affords  an  explanation  of  the  superior  power 
of  steam  in  atomizing  liquid  fuel.  A  study  of  distillation 
shows  three  sorts  of  petroleum  suitable  for  fuel. 

(A)  Natural  oils  which  have  parted  with  their  volatile 
portions  under  the  influence  of  sun  and  air  and  become 
natural  mazut. 

Borneo  oil  which  flashes  at  100°C.  =  212°F.  is  directly 
employed  as  fuel,  and  Texas  oil  appears  to  possess  little 
other  value  than  as  fuel. 

(B)  Distillation  residues,  or  mazut,  which  result  from 
boiling  off  all  the  more  volatile  portions. 


CHEMICAL  PROPERTIES   OF    PETROLEUM        65 

(C)  American  distilled  oils  as  per  page  44.  These  oils 
are  very  homogeneous  and  regular,  but  they  emit  in- 
flammable vapours  below  the  temperatures  at  which  they 
boil. 

The  Physical  Properties  of  Petroleum. 

These  have  already  been  partly  treated  of  under  the  previous 
head,  but  it  may  be  added  that  in  common  with  all  hydro- 
carbons and  fats,  petroleum  and  other  liquid  fuels  become  more 
fluid  and  lose  much  of  their  viscidity  when  heated.  Their 
fluidity  increases  rapidly  with  heat.  Hence  the  better  atomiza- 
tion  possible  with  heated  oils.  Tests  at  Cherbourg  on  mazut 
at  different  temperatures  show  that  flow  of  oil  through  an  orifice 
of  annular  form  half  a  millimetre  wide  was  as  follows  in  cubic 
centimetres  per  minute — 

Temperature   .      .      .      6°C.          15°       35°          70°        100° 
Flow 2-5  6-5      32         188         466 

With  water  at  19°C.,  the  flow  was  4,300  c.cm. 

Mazut  is  easily  heated,   its  specific   heat  being   0*42. 

Petroleum  has  a  rapid  expansion  coefficient,  as  much  as 
0-0007  per  degree  Centigrade.  This  helps  it  to  rid  itself  of 
water  because,  by  heating  the  oil,  both  its  sp.  gr.  and  its  re- 
sistance are  reduced,  and  water  can  the  more  easily  gravitate 
out. 

Though  petroleum  has  been  supposed  to  be  unaffected  by 
storage,  mazut  changes  when  exposed  to  air  even  more  rapidly 
than  coal,  according  to  M.  Bertin,  losing  its  fluidity  and  parting 
with  some  of  its  calorific  power  ;  experiment  seems  to  be  want- 
ing in  regard  to  such  changes  taking  place  in  closed  tanks  and 
not  exposed  to  air.  Any  loss  that  may  have  been  experienced 
may  perhaps  be  attributed  to  a  gradual  evaporation  of  lighter 
oils  still  remaining.  The  lighter  oils  do  possess  the  highest 
calorific  capacity,  and  their  loss  would  therefore  to  some  extent 
reduce  the  calorific  capacity  of  the  residue. 

In  Russia  the  sp.  gr.  of  oil  for  steam  raising  purposes  at 
17-5°C.  —  63-5°F.  must  not  exceed  911  to  912,  and  oil  must 
contain  no  water,  sand  or  alkali.  When  received  the  tempera- 
ture must  not  exceed  50°C.  =  122°F.  and  the  flash  point  must 
be  above  140°  or  150°C.  =  284°  to  302°F. 

Certain  railroads  stipulate  a  density  of  905  to  915  at  14°R. 
=  63-5°F.  There  is  no  viscosity  clause. 

The  Navigation  Co.  Caucase  Mercure  ask  for  a  density  of 
926.  The  Russian  Navyaccepts  a  flash  point  of  100°C.  =212°F. 
and  a  density  of  950.  In  America  the  minimum  flash  point  of 
200°F.  is  usual  =  93'3°C. 


66  LIQUID  FUEL  AND  ITS  APPARATUS 

Water  in  Oil. 

To  determine  the  water  q  the  density  d  is  found  of  the  sample. 
After  heating  for  some  time  at  103°C.  =  217-5°F.  the  density 
is  again  found  =d2.  The  quantity  of  water  q  is  determined 
by  this  relation  (1—  q)  d2  +  q  =  d. 

The  coefficient  of  expansion  per  degree  C.  is  assumed  to  be 
0-000735  =  0-000408  per  degree  F. 


MATERIALS. 

In  the  utilization  of  fuels  for  steam-raising  it  is  necessary  to 
have  a  knowledge  more  or  less  full  of  the  whole  of  the  materials 
which  will  be  employed  either  as  fuels  or  structurally.  Some- 
thing must  also  be  known  of  the  environment  in  which  such 
substances  will  be  employed. 

A  list  of  substances  with  which  the  engineer  will  be  required 
to  deal  therefore  includes,  besides  the  fuel  itself,  air,  water, 
cast-iron,  steel,  fire-brick,  etc. 

The  conditions  include  the  ordinary  atmospheric  tempera- 
tures and  moisture,  the  pressure  of  the  atmosphere,  and  so  on. 

The  units  in  which  ideas  are  expressed  must  also  be  clear. 

With  this  object  separate  sections  have  been  given  to  the 
subjects  of  Water,  Air,  and  Heat  in  its  various  forms,  to  carbon 
and  hydrogen,  the  only  two  practicable  fuels.  A  few  notes 
are  given  below  concerning  some  of  the  other  materials. 

Cast-iron  cannot  be  employed  in  the  furnace,  for  it  is  rapidly 
destroyed  by  the  action  of  fire,  even  when  not  directly  in  the 
flame.  It  should  not  be  employed  in  the  retort  in  which  to 
heat  and  to  gasify  even  the  h'ght-burning  oils.  Cast-iron  tubes 
have  been  tried  for  this  purpose,  and  have  been  found  to  become 
choked  by  a  deposit  of  carbon,  which  may  probably  be  due 
to  some  affinity  between  the  carbon  in  the  iron  and  that  in  the 
oil. 

Cast-iron  should  never  be  employed  as  a  material  for  any 
vessel  exposed  to  internal  pressure. 

Steel. 

Steel  is  par  excellence  the  material  for  all  parts  of  boilers. 
Like  cast-iron,  it  will  not  withstand  furnace  temperatures 
except  when  backed  by  water,  as  in  the  case  of  the  plates  of  a 
boiler. 

Steel  tubes  only  -^  in.  thick  are  employed  by  Clarkson  as 
the  retort  coil  in  which  paraffin  is  vaporized.  These  coils  are 
in  the  zone  of  flame,  and  vaporize  the  oil  on  its  way  to  the 


FIRE-CLAY  AND  FIRE-BRICK  67 

burner  which  they  surround.  They  possess  a  fair  durability 
owing  to  the  heat  absorbing  power  of  the  vaporizing  liquid, 
and  they  are  found  to  keep  free  of  carbon  deposit. 

F  ire-Bricks. 

The  most  important  material  for  the  furnace  engineer  is 
fire-clay,  a  material  which  is  found  beneath  seams  of  coal. 

In  a  properly-set  boiler  for  coal  burning  the  whole  interior 
of  the  furnace  and  combustion  chamber  will  be  more  or  less 
fluxed  and  run  partially  into  drops  or  stalactites,  which  hang 
from  projecting  edges.  With  liquid  fuel,  fire-brick  is  a  most 
necessary  material  for  promoting  combustion.  It  is  a  bad 
conductor  of  heat,  and  has  the  property  of  resisting  high 
temperatures  known  as  refractoriness.  High  furnace  tempera- 
tures will  render  even  many  fire-clays  liquid  at  the  surface. 

Ordinary  fire-clays  contain  58  to  62  per  cent,  of  silica,  36  to 
38  per  cent,  of  alumina,  and  from  1  to  3  per  cent,  of  ferric  oxide. 

A  large  content  of  silica  denotes  a  good  and  refractory  brick. 

Dowlais  fire-brick  contains  97  J  per  cent,  of  silica  and  less 
than  2  per  cent,  of  alumina,  the  remainder  being  oxide  of  iron, 
with  a  trace  of  lime  and  magnesia. 

Ganister,  which  is  so  much  used  in  steel  work,  contains  89 
per  cent,  of  silica,  5|  of  alumina,  2J  of  iron  oxide,  and  2|  per 
cent,  of  material  which  is  lost  in  burning. 

A  brick  used  in  France  is  made  from  diatomaceous  earth 
which  is  nearly  pure  silica.  These  French  bricks  are  very 
porous  and  light,  and  when  dry  will  float  in  water. 

The  best  fire-clay  comes  from  Stourbridge  and  Newcastle 
in  England,  Glenboig  in  Scotland,  and  Dinas  in  Wales. 

Makers  of  fire-brick  supply  a  great  variety  of  shapes,  and 
blocks  can  be  had  for  seating  purposes  or  for  furnace  work, 
notably  for  over-fire  arches  and  combustion  chambers. 

Fire-bricks  are  also  made  for  threading  on  water  tubes,  so 
as  to  build  up  refractory  walls  upon  water  tubes  for  the  purpose 
of  securing  the  correct  direction  of  gases  and  for  promoting 
perfect  combustion  and  smokelessness.  It  is  said  that  car- 
borundum is  very  refractory  indeed,  and  that  when  finely 
powdered  and  made  into  a  paint  with  soluble  glass  or  silicate 
of  soda,  and  painted  on  bricks,  it  will  greatly  assist  in  their 
preservation.  Or  the  bricks  may  be  dipped  in  the  solution. 
The  carborundum  surface  is  then  most  refractory. 

Too  little  attention  is  paid  by  engineers  to  the  fire-bricks 
they  use,  and  heavy  expenses  are  incurred  in  maintaining 
furnaces,  expenses  quite  needless  if  proper  attention  is  paid 
to  the  selection  of  the  bricks. 


68  LIQUID  FUEL  AND   ITS  APPARATUS 

When  a  furnace  is  to  be  repaired  bricks  are  often  purchased 
from  the  nearest  wharf,  where  they  have  lain  exposed  to 
weather  for  weeks.  In  their  water-saturated  condition  they 
are  built  into  the  furnace  and  exposed  to  the  full  heat,  with  the 
result  that  the  interior  of  the  bricks  is  disintegrated  and  the 
bricks  split  up  at  once. 

When  a  fire-brick  is  made  it  should  be  fired  at  a  tempera- 
ture as  high  as  that  to  which  it  will  be  exposed  when  at 
work. 

The  composition  of  bricks  has  a  great  influence  upon  their 
durability  in  certain  surroundings.  A  silica  brick  will  run  like 
treacle  in  certain  surroundings,  and  an  alumina  brick  will  fail 
in  others,  but  a  brick  of  alumina  is  as  refractory  as  one  of  silica 
— indeed,  more  so  as  regards  its  ability  to  withstand  high 
temperatures. 

Having  secured  the  right  kind  of  brick,  a  sufficient  supply 
ought  to  be  kept  in  store  to  enable  them  to  become  dry  before 
use.  When  built  into  place,  a  slow  fire  only  must  be  made  and 
the  heat  got  up  gradually,  so  as  to  allow  the  bricks  to  dry 
thoroughly  before  being  highly  heated.  When  a  boiler  is  laid 
off  from  work  it  should  be  closed  up  completely  by  shutting 
the  dampers  and  leaving  the  boiler  and  its  brickwork  to  cool 
as  slowly  as  possible. 

The  most  troublesome  detail  of  a  furnace  is  the  arching 
over  the  fire  of  a  water  tube  boiler.  The  usual  form  of  water 
tube  boiler  is  very  smoky,  and  to  cure  this  furnace  must  be 
covered  by  a  brick  arch,  and  a  capacious  combustion  chamber 
must  be  employed  beyond  this,  so  that  the  furnace  gases  and 
the  air  admitted  above  the  fire  may  become  well  mixed  and 
burned  at  a  high  temperature.  Even  with  the  best  of  bricks 
these  arches  are  apt  to  fail  when  first  fired,  the  face  of  the  bricks 
dropping  off. 

Messrs.  E.  and  J.  Pearson,  of  Stourbridge,  make  a  special 
brick  for  these  wide  flat  arches,  and  supply  a  special  cement 
for  use  in  putting  them  together.  The  cement  is  easily  fluxed 
by  heat,  and  cements  the  whole  surface  of  the  arch  into  a  solid 
face,  so  that  pieces  of  the  brick  cannot  fall  out.  In  time  the 
whole  arch  welds  into  a  solid  mass. 

Such  an  arch  ought  to  be  built  of  properly-shaped  bricks. 
If  plain  rectangular  bricks  are  used  the  arch  pressure  becomes 
concentrated  upon  the  intrados,  and  tends  to  flake  off  the 
bricks  and  deprive  the  arch  of  its  sustaining  power.  The 
bricks  should  be  of  taper  form  so  that  they  fit  close  in  the  arch. 
What  are  known  as  blocks  are  used  for  these  arches  and  for 
similar  purposes,  and  the  above  fire-brick  manufacturers  make 


FIRE-CLAY  AND  FIRE-BRICK  69 

special  arch  blocks  with  a  tongue  and  groove  joint  for  better 
security. 

In  the  formation  of  all  important  fire-clay  blocks  that  will  be 
exposed  to  stress,  as  is  an  arch,  it  is  of  serious  importance  that 
the  clay  be  properly  pugged  into  the  mould.  It  is  bad  practice 
to  put  a  block  of  clay  into  the  mould  and  put  it  under  mechani- 
cal pressure  so  as  to  force  it  to  fill  the  mould.  When  this 
pressure  method  is  followed  the  plastic  clay  will  be  internally 
fractured.  Shearing  planes  are  developed  which  form  planes 
of  cleavage  or  fracture.  The  movement  may  be  very  slight, 
but  lines  of  weakness  will  be  developed  and  the  homogeneous 
continuity  of  the  mass  of  the  clay  will  be  destroyed.  When 
burnt,  the  adhesion  along  these  planes  of  weakness  will  be 
imperfect  and  when  at  work  such  a  block  will  fail. 

A  really  good  arch  should  last  a  year  if  built  from  a  firm 
springing.  The  thrust  of  an  arch  is  considerable  and  must  all 
be  taken  by  the  side  walls,  which,  not  as  a  rule  carrying  the 
weight  of  the  boiler,  may  not  be  very  stable,  and  it  is  desirable 
to  tie  them  down  to  the  foundation  by  through  vertical  bolts, 
so  as  to  form  a  stiff  unyielding  support  for  the  arch  springing. 

The  subject  of  fire-brick  is  one  that  has  not  been  much 
studied  by  engineers.  Steel  melters  and  others  who  deal  with 
high  temperatures  have  paid  attention  to  the  question.  The 
burning  of  coal  for  steam  raising  purposes  has,  however,  been 
so  invariably  carried  out  at  comparatively  low  temperatures 
that  the  importance  of  fire-brick  has  not  been  perceived.  When 
a  steam  engineer  begins  to  experience  trouble  with  his  furnace 
side  wall  lining  he  casts  about  him  for  some  means  of  meeting 
that  trouble,  and  his  efforts  may  take  the  shape  of  a  water  box. 
High  temperature  he  regards,  when  it  occurs,  as  a  disagreeable 
incident,  to  be  checked  and  avoided.  If  he  understood  com- 
bustion he  would  welcome  the  temperature  as  a  means  of 
securing  more  perfect  combustion,  and  would  endeavour  to 
meet  the  trouble  by  the  provision  of  suitable  fire-brick. 

The  high  temperatures  obtainable  with  oil  fuel  bring  the 
fire-brick  problem  into  greater  prominence,  and  direct  attention 
to  this  most  important  material. 

Some  fire-bricks  in  a  very  hot  furnace  will  soften  and  melt 
away  under  long  sustained  heat.  Others,  more  refractory  or 
infusible,  crack  and  split  up  under  sudden  temperature  changes. 
A  good  brick  becomes  surface  glazed,  but  the  body  remains 
rough  and  porous.  A  granular  nature  and  porous  structure 
are  considered  essential,  and  fire-bricks  are  not  made  of  all  new 
clay.  Old  bricks  are  granulated  and  mixed  up  with  the  new 
clay,  so  that  the  necessary  texture  is  secured. 


70  LIQUID  FUEL  AND  ITS  APPARATUS 

Fire-clay  is  a  mixture  of  silica  and  alumina  in  varying  pro- 
portions, each  constituent  possessing  its  own  peculiar  charac- 
teristics. Usually  silica  exists  in  the  proportions  of  about 
two-thirds  to  one-third  of  alumina.  The  presence  of  alkaline 
matter  is  prejudicial  and  induces  fluxing.  Thus  lime  is  in- 
tensely refractory  of  itself,  and  so  is  magnesia,  but  both  of  these 
infusible  substances  fuse  easily  with  silica,  as  also  do  oxides 
of  iron,  soda,  potash  and  other  alkalies.  These  impurities  of 
fire-clays  must  be  avoided.  Mixing  two  clays  of  good  quality 
will  not  necessarily  prove  a  success. 

Silica,  if  otherwise  pure,  gives  perhaps  the  most  refractory 
bricks,  and  certain  French  fire-bricks  are  made  from  infusorial 
earth  which  consists  of  the  minute  siliceous  shells  of  the  diatom- 
aceae.  These  French  bricks,  when  dry,  will  float  in  water,  their 
specific  gravity  being  under  1,000,  owing  to  the  numerous 
voids  and  pores,  but  they  are  very  tender  and  do  not  stand 
well  at  the  fire-grate  level,  where  a  tougher  and  harder  brick  is 
necessary.  The  Dinas  bricks  of  South  Wales  are  very  siliceous, 
but  are  liable  to  split  up  if  suddenly  cooled,  and  are  therefore 
somewhat  unsuitable  for  hand-fired  furnaces,  but  should  be 
excellent  for  mechanically-stoked  furnaces  with  self-cleaning 
grates.  Probably  the  best  boiler  furnace  brick  is  one  high  in 
silica,  yet  containing  a  fair  proportion  of  alumina  and  free  from 
alkalies.  Such  a  brick  combines  infusibility  and  toughness 
for  puddling  furnaces,  coke  ovens,  gas  retorts  and  other  high 
temperature  uses,  and  it  must  be  remembered  that  the  kind 
of  furnace  advised  by  the  author  for  bituminous  fuel  com- 
bustion, and  adopted  from  sheer  necessity  with  liquid  fuel,  is 
exposed  to  temperatures  more  resembling  those  of  metallurgical 
furnaces  than  the  starved  temperatures  of  the  common  un- 
scientifically set  steam  boiler. 

A  sample  of  the  clay  from  the  Glenboig  Star  Mine,  as  analysed 
by  Edward  Riley,  F.C.S.,  after  calcination,  gave  the  folio  wing 
results — 

Per  cen\ 

Silica 65-41 

Titanic  acid 1-33 

Alumina 30-55 

Peroxide  of  iron 1-70 

Lime 0-69 

Magnesia  , 0-64 

Potash  and  soda  .  0  •  55 


100-87 
Sir  Frederick  Abel  analysed  a  Glenboig  brick,  at  the  Royal 


FIRE-CLAY  AND  FIRE-BRICK 


71 


Arsenal,  Woolwich,  as  follows.     The 'brick  was  taken  from 
stock — 

Per  cent. 

Silica 62-50 

Alumina 34-00 

Iron  peroxide 2-70 

Alkalies,  loss,  etc 0-80 


100-00 

Mere  analysis,  however,  does  not  tell  everything.  For 
instance,  in  this  last  analysis  the  silica  and  alumina  were  largely 
in  chemical  combination,  and  this  is  more  valuable  than  the 
mere  mechanical  combination  of  the  constituents. 

To  make  a  good  brick  the  clay  must  be  suitably  weathered 
so  that  any  iron  nodules  may  separate  out.  The  clay  is  ren- 
dered smoother  and  more  solid  for  articles  requiring  such 
qualities,  as  seating  blocks  ;  for  high  temperatures,  porosity 
is  given  by  the  addition  of  old  bricks. 

All  defects  of  shape  are  produced  in  the  drying  stove  after 
moulding.  Stoving  is  therefore  a  most  important  operation, 
and  a  brick  must  be  practically  dry  before  firing,  which  is 
gentle  at  first  until  the  bricks  are  hot  and  perfectly  dried  out. 
Then  the  kiln  is  put  on  to  full  fire,  and  the  temperature  must  be 
maintained  until  the  bricks  cease  to  shrink.  A  brick  which 
has  not  been  fired  at  a  full  temperature  will  shrink  further  if 
put  to  work  at  a  higher  temperature.  The  total  shrink  from 
the  moulded  size  is  about  8 \  per  cent,  of  the  bulk,  or  about  2 
per  cent,  linear  measure.  In  any  case  no  shrinkage  should 
remain  in  a  brick,  or  it  will  shrink  when  put  to  work  and  pull 
the  brickwork  in  pieces. 

Professor  Abel,  F.R.C.,  gave  various  analyses  of  fire-clays 
as  per  the  annexed  table,  from  which  the  excellence  of  Stour- 
bridge  and  Glenboig  bricks  is  plainly  evident  in  the  small 
percentage  of  alkalies. 


Description  of  Fire-clay. 

Silica. 

Alumina. 

Iron 
Peroxide. 

Alkalies, 
Loss,  etc. 

Kilmarnock  
Stourbridge  

5940 
65-65 
67-00 

35-76 
26-59 
25-80 

2-50 
5-71 
4-90 

2-64 
2-05 
2-30 

66-47 

26-26 

6-33 

0-64 

58-48 

35-78 

3-02 

0-72 

63-40 

31-70 

3-00 

1-90 

Newcastle      

59-80 
63-50 

27-30 
27-60 

6-90 
6-40 

6-00 
6-50 

Glenboig        

62-50 

34-00 

2-70 

0-80 

1$  LIQUID  FUEL  AND  ITS  APPARATUS 

For  the  following  miscellaneous  information  the  author  is 
indebted  to  the  Glenboig  Company — 


Shape  and  Size. 

Weight. 

,000  Square  Bricks   

Inches. 
9  X  4|  X  3    — 

Tons. 
4 

,000 

9  X41  X21  — 

31 

,000             „                

9  x4J  x2|  — 

"3 

3 

,000  End  or  Side  Arch 
,000           „             „                ... 
,000           „             „                ... 
,000  Cupola    
,000  Pup  Bricks        

.    9  x  4  J  x  3    and  2 
.    9x4^x2|  and  1| 
.    9x4^x3    and  21 
9  x  4£  and  3x3 
9  x  3    x  2£  — 

3* 
2| 
3f 

3J 

2 

,000          „                   

9x2|x2£  — 

11 

1,000  Scone  Blocks     

9  x4|  x2   — 

-1  3 

si 

1,000           „                  

9x4|xl|  — 

^3 

2 

1,000  Crown  or  square 

9x6    X3   _ 

51 

•*l 

One  inch  =Millimetres  25-4.         One  Ton  =  Kilogrammes  1,016. 


Miscellaneous  Weights  and  Measurements. 

STACKED    LOOSE. 

1,000  9  in.  x4£  in.  x2£  in.  =66  cub.  ft. 
1,000  9  in.  x4J  in.  x3  in.  x3  in.  =80  cub.  ft 

BUILT   WITH   FIRE-CLAY. 

1  square  yard  9  in.  work  requires : — 

109  bricks  9  in.  x  4|  in.  x  2£  in.  and  2  cwts.  ground  fire-clay,  or  92  bricks 

9  in.  x4|  in.  x3  in.  and  If  cwts.  ground  fire-clay. 

A  rod  (English)  of  brick  =  11J  cub.  yds. 

A  rood  (Scotch)  of  brick  =  16  cub.  yds. 

FOR  PAVING. 

1  yard  superficial  requires  16  tiles  9  in.  x9  in. 

18  tiles  12  in.  x6  in.  x2  in. 
32  bricks  9  in.  x  4|  in.  x  3  in.  laid  flat. 
48  bricks  9  in.  x  4|  in.  x  3  in.  laid  on  edge. 
One  9  inchx4|  in.  x3  in.  =9  Ib. 
17|  cub.  ft.  blocks  =  1  ton. 

334  bricks  =  1  load. 
1,500  to  2,000  =  1  railway  truck. 

3,100  to  3,200  9  in.  x  4^x21  in.  bricks  =  1  railway  truck  (Continental) 
6  to  8  tons  ground  fire-clay  =  1  railway  truck. 
8  bags  ground  clay  =  l  ton. 
3  casks  ground  clay  =  l  ton. 

21  cub.  ft.  of  dry  ground  fire-clay,  firmly  packed  =  1  ton. 
Fire-clay  suffers  no  deterioration  of  quality  from  rain. 

For  shipment  it  is  packed  in  barrels  or  bags. 
The  usual  shipping  size  of  fire-brick  is  9  in.  x  4|  in.  x  2|  in. 

The   Glenboig   Company   make   special   silica   bricks   from 
English   chalk  flints;    they  weigh  2  tons   12  cwt.  per  1000, 


FIRE-CLAY  AND  FIRE-BRICK 


73 


9  in.  X  4J  in.,  x  2J  in.  They  also  make  a  highly  refractory 
brick  from  Gartcosh  clay,  which  analyses  as  below,  according 
to  W.  WaUace  and  Jno.  Clark,  Ph.D.,  F.C.S.,  etc.— 


Silica    .      .      . 
Titanic  acid     . 
Alumina 
Peroxide  of  iron 
Lime     . 
Magnesia    . 
Potash        .      . 
Soda 


Per  cent. 

61-90 
2-09 

32-34 
3-02 
0-37 
0-20 
0-06 
0-30 

100-28 


The  proportion  of  alkalies  is  thus  small  and  the  brick  is 
solid  and  has  small  shrinkage  from  the  mould  and  weighs  131 
pounds  per  cubic  foot.  The  ganister  bricks  of  the  Company, 
which  are  made  from  what  appears  to  be  a  soft  sandstone, 
analyse  as  below — 


Gartcosh  Ganister. 

Gartcosh  Silica. 

Silica     
Titanic  acid                  , 

87-06 
Trace 

74-10 

0-20 

Alumina      

11-24 

22-32 

Oxide  of  iron        
Lime      

0-69 
Trace 
Trace 

2-28 
0-48 
0-34 

Potash  

0-61 

Soda      

0-33 

0-38 

99-93 

100-00 

Bricks  for  Oil-fired  Furnaces. 

Where  bricks  are  applied  to  oil-fired  furnaces  the  intense 
local  heat  of  the  oil  furnace  of  course  burns  the  brickwork 
away  in  time,  or  rather  melts  it  on  the  surface  immediately 
in  contact  with  the  flame,  causing  it  to  run  down  and  hang  in 
the  form  of  stalactites,  but  it  takes  a  considerable  time  to  wear 
through  nine  inches  of  brickwork,  and  the  cost  of  the  bricks 
is  more  than  compensated  for  in  the  increased  efficiency  of  the 
furnace. 

It  is  often  the  case  that  furnaces  and  combustion  chambers 
lined  with  fire-brick  come  to  grief  through  being  badly  built 
rather  than  from  the  bad  quality  of  the  bricks  used  ;  at  the 
same  time,  good  work  will  not  make  up  for  bad  bricks.  The 
usual  type  of  liquid  fuel  furnace  for  kilns  is  as  shown  in  the 


74 


LIQUID  FUEL  AND  ITS  APPARATUS 


annexed  illustration,  Fig.  1,  the  burner  being  so  set  that  the 
fuel  in  vaporized  form  is  more  or  less  concentrated  in  the  centre 
arch  at  x.  The  consequence  is  that  the  intense  heat  is 
localized  and  the  brickwork  runs  down  into  slag.  Various 
methods  have  been  tried  to  get  over  the  difficulty — one  is  to 
cover  the  grate  with  broken  fire-brick,  or  coke,  but  this  was  not 
altogether  successful.  Another  idea  is  to  protect  the  piers 


x 


Fig.    1. 


of  the  arches  with  bricks  piled  up  loosely  in  semicircular  form, 
with  the  concave  side  facing  the  burner,  stacking  them  with  a 
space  between,  and  crossing  the  open  space  with  another  row 
of  bricks,  as  shown  in  plan,  Fig.  2,  thus  distributing  the  heat 
over  a  large  area  of  brick  surface. 

The  bricks  would  melt  after  a  time,  but  they  could  be  raked 
out  and  a  fresh  lot  put  in,  and  the  arches  would  be  saved  con- 
siderably. 


2. 


In  the  case  of  over-fire  arches,  Fig.  3,  for  water  tube  boilers 
having  a  wide  span,  the  best  type  of  brick  to  use  is  what  is 
known  by  the  name  of  the  Bullhead  or  End-  wedge,  as  shown 
in  Fig.  4,  or  the  special  bricks  of  Fig.  5. 

In  all  cases  fire-bricks  should  be  set  with  as  little  jointing 
material  as  possible,  and  for  arches  the  bricks  should  be  speci- 
ally made  to  work  to  the  desired  radius.  Any  attempt  to  use 


FIRE-CLAY  AND  FIRE-BRICK 


75 


SECTION  ON  A  B 


r 


ELE  v  ATION 


Fig.  3. 

ordinary  rectangular  bricks  is  fatal.  The  pressure  becomes 
concentrated  on  the  underside  of  the  arch,  as  in  Fig.  6,  and  the 
mass  has  no  rigidity — bricks  begin  to  fall  out  and  the  arch  is 
ruined. 

The  bricks  should  be  set  with  finely  ground  fire-clay  made 
up  with  water  to  the  consistency  of  thick  paint.  The  brick 
should  be  dipped  in  this,  and  then  rubbed  into  contact  with  its 
neighbours. 

Fire-clay  is  made  up  into  specially  shaped  bricks  and  lumps 
for  different  purposes,  and  bricks  and  blocks  can  be  made  to 
meet  the  special  requirements  in  furnace  work,  but  unequally 
proportioned  lumps  must  be  avoided  on  account  of  internal 
stresses,  fire-clay  having  its  limitations  in  this  respect,  as  ex- 
plained above,  just  as  cast-iron  has  The  best  plan  is  to  con- 


76 


LIQUID  FUEL  AND  ITS  APPARATUS 


suit  a  reputable  maker.     The  most  usual  course  is  to  decide 
on  all  other  points  of  construction  and  make  the  best  job 


»*•  * 


LARGE 


ARCH    6RIC* 


possible  on  what  are  generally  considered  incidentals,  such  as 
furnace  linings,  whereas  by  taking  the  limitations  of  a  necessary 
material  into  consideration  in  the  first  place,  much  expense  and 

trouble  may  be  saved. 

Good  fire-bricks  should 
have  sharp  angles,  and 
give  a  metallic  ring  on 
being  rubbed  together. 
They  should  be  kept  some 
time  before  use  in  a  dry 
place.  Bricks  sodden  with 


rain  and  heated  up  quickly 
SPRINGER  will  tend  to  burst. 

Fig.  5.  Various  substances  hav- 

ing been  suggested  as  sub- 
stitutes for  fire-brick,  it  may  not  be  out  of  place  to  say 
something  as  to  the  varieties  of  fire-clay  goods. 

The  following  is  the  classification  generally  adopted — 

I  Siliceous  fire-clay  goods. 

II  Aluminous       „         „ 

III  Argillaceous     „         „ 

IV  Carboniferous  „         „ 

Nos.  I  and  II  are  the 
most  generally  used. 

No.  IV  is  a  mixture 
of  carbon  and  clay,  the 
carbon  being  in  a  crys- 
tallized state  as  used 
for  arc  lamps,  etc.,  or 
amorphous  as  graphite, 
the  latter  being  used 
for  the  manufacture  of  crucibles,  etc.  Carbon  blocks  have 


Fig.  6. 


FIRE-CLAY  AND  FIRE-BRICK  77 

been  suggested,  but,  apart  from  the  excessive  cost,  the  carbon 
combines  with  any  free  oxygen  in  the  furnace  gases  and  is 
consumed. 

No.  II.  A  mixture  containing  a  greater  portion  of  alumina 
than  pure  clay.  This  also  is  too  costly  for  general  use. 

Lime  is  sometimes  used  as  furnace  lining  for  electrical  kilns 
and  will  withstand  the  intense  heat  of  the  voltaic  arc,  but  as  it 
retains  the  property  of  being  hydrated  in  air,  its  use  is  neces- 
sarily very  limited.  This  class  of  fire-clay  goods  is  known  as 
basic. 

Siliceous  fire-clay  goods  are  composed  almost  exclusively  of 
silica. 

Argillaceous  fire-clay  goods  are  composed  of  silica  and  alumina, 
and  are  next  in  degree  of  refractoriness  to  aluminous  goods. 

It  should  be  borne  in  mind  that  the  foregoing  are  each 
adapted  to  particular  purposes,  and  the  proper  admixture  of 
clays  for  any  desired  purpose  is  a  matter  that  only  long  experi- 
ence and  scientific  knowledge  can  determine,  the  physical  as 
well  as  the  chemical  properties  of  clay  having  to  be  taken  into 
account. 

SUoxicon. 

A  very  refractory  material  is  Siloxicon,  a  product  of  the 
electric  furnace,  consisting  of  carbon,  silicon  and  oxygen  formed 
at  a  temperature  of  4,000°  to  5,000°F.,  and  therefore  very 
refractory  at  ordinary  temperatures.  It  is  a  loosely  coherent 
mass  as  formed  and  is  ground  to  pass  a  40 2  sieve.  It  is  an 
amorphous  grey-green  compound  when  cold,  becoming  light 
yellow  at  300°F.  It  is  insoluble  in  molten  iron,  neutral  to 
acid  and  basic  slag,  indifferent  to  all  save  hydrofluoric  acid, 
and  is  unattacked  by  hot  alkaline  solutions.  It  is  formed  into 
bricks  by  simple  pressure,  when  damp,  and  fired.  It  is  neutral 
to  clays  and  will  not  oxidize,  and  appear  likely  to  form  a  valu- 
able furnace  lining  where  oil  fuel  is  employed. 


CHAPTER    V 


COMBUSTIBLES     AND     SUPPORTERS     OF     COMBUSTION 

Carbon. 

RBON  is  an  element  which  has  the  following  properties. 
Its  atomic  weight  is  12  and  it  is  tetravalent  in  chemistry. 
It  is  found  free  in  nature  in  various  forms,  but   is  usually 
considered  to  exist  only  in  three  allotropic  modifications,  viz. — 

(1)  The   Diamond,   which   is   practically   pure   crystallized 
carbon. 

(2)  Graphite,  not  entirely  amorphous. 

(3)  Charcoal,    an    amorphous   substance,  is  considered    to 
include  all  other  forms  of  carbon. 

The  following  figures  give  the  values  of  the  various  forms 
of  carbon  in  calorific  value  or  heat  absorption — 

COMBUSTION. 


State  of  1  pound  or  1  kilo,  of  Carbon. 

Product  of 
Combustion. 

Calories 
per  kilo. 

B.Th.U. 

per  pound. 

CO 

2,175 

3  915 

CO2 

7,859 

14,146 

CO2 

7  900 

14  222 

Amorphous   
»             

CO 
C02 
CO 

2,453 
8,137 
5,684  +e 

4,415 
14,647 
10,232  +e 

OOo 

11  370  +e 

20  463  +e 

2£  pts.  of  CO  per  part  of  C.     . 

CO2 

5,683 

10,231 

HEAT  ABSORBED  BY  METAMORPHIC  CONVERSION. 


Diamond  . 

....      to 

Vapour 

3,508 

6,316 

Graphite 
Amorphous   . 

3,468 
3,231 

6,241 
5,817 

Graphite 

41-5 

74-7 

Graphite 

.      •      •      •       „ 

Amorphous 

277-0 
235-7 

499-0 
424-3 

78 


COMBUSTIBLES  AND  SUPPORTERS  79 

The  above  figures  are  calculated  from  the  determinations 
by  Berthelot  of  the  heat  of  combustion  and  formation  of  the 
molecule  (see  Thermochimie,  par  M.  Berthelot,  Paris,  1897). 

Except  that  these  figures  point  the  lessons  that  form  and 
state  are  dependent  upon  heat,  apparent  or  latent,  no  further 
interest  centres  on  the  crystalline  modification  of  carbon, 
which  is  too  scarce  to  employ  as  a  commercial  fuel. 

The  first  oxidation  of  ordinary  carbon  with  one  atom  of 
oxygen  to  CO  produces  4415  B.Th.U.  =2,453  cal.  per  pound 
and  per  kilogram  respectively. 

The  second  oxidation  produces  a  further  10,231  B.Th.U.— 
5,684  cal.  The  total  heat  produced  by  complete  combustion 
is  thus  14,647  B.Th.U.  =8, 137  cal. 

The  difference  (5,684-2,453)  between  the  two  oxidations 
is  5,817  B.Th.U.=  3,231  cal.,  and  Berthelot  considers  that  this 
difference  is  less  than  the  latent  heat  of  vaporizing  carbon  by 
some  unknown  amount.  In  the  absence  of  a  knowledge  of 
what  it  amounts  to,  it  is  usual  to  say  that  the  difference  is  the 
latent  heat  of  vaporizing  carbon,  just  as  967  is  the  latent  heat 
of  steam. 

In  order  to  liquefy,  carbon  mast  absorb  heat,  but  free  liquid 
carbon  is  unknown.  Solid  carbon  burns  directly  to  dioxide 
gas  without  going  through  the  intermediate  liquid  state, 
exactly  as  a  piece  of  ice  will  disappear  in  a  dry  cold  wind  below 
freezing  temperature  without  passing  through  the  intermediate 
state  of  water.  The  liquid  state  is  not  imperative,  and  carbon 
is  only  found  liquid  when  combined  with  other  substances. 
It  forms  a  liquid  with  sulphur  as  carbon  bisulphide  CS2.  It 
is  liquid  with  hydrogen  and  oxygen  in  alcohol,  and  it  is  liquid 
with  hydrogen  alone  in  the  many  hydrocarbons  with  which  we 
are  at  present  concerned.  By  so  much  as  the  liquid  form 
already  represents  heat  rendered  latent  in  reducing  a  solid  to  a 
liquid,  by  just  so  much  should  liquid  fuel  possess  a  greater 
calorific  value  per  unit  of  its  contained  carbon  than  a  similar 
weight  of  solid  fuel.  The  same  argument  applies  with  equal 
force  to  the  hydrogen,  but  to  some  extent  conversely.  The 
calorific  capacity  of  hydrogen  is  given  in  terms  of  the  gas 
burned  as  gas.  In  solid  coal  the  hydrogen  is  part  of  a  com- 
pound solid,  and  it  is  scarcely  correct  to  calculate  the  calorific 
capacity  of  a  solid  fuel  in  terms  of  its  hydrogen  at  gas  value, 
for  undoubtedly  heat  is  absorbed  in  rendering  the  hydrogen 
gaseous  from  its  solid  combined  state  in  coal.  Similarly,  in 
liquid  fuel  the  hydrogen  is  in  liquid  form  and  must  be  gasified. 
It  is  possible  that  the  benefit  derived  from  the  liquidity  of  the 
carbon  is  neutralized  by  the  liquidity  of  the  hydrogen. 


80  LIQUID  FUEL  AND  ITS  APPARATUS 

The  properties  of  carbon  are  summarized  in  the  following 
table — 

PROPERTIES  OF  CARBON. 

Atomic  weight 12 

Specific  heat 0-1468  to  0-285 

Heat  of  combustion  per  kilo,  to  CO2       .  8,137  cal.  =32,285  B.Th.U. 

„     „  „  „  pound  to  CO2   .  14,647  B.Th.U.  =3,691  cal. 

Temperature  of  vaporization        .      .      .  3,600°C.=6,512°F. 
„           „  combustion  to  CO 

In  air    .....  1,485°C.  =2,705°F. 

In  oxygen        .      .      .  4,292°C.  =7,757°F. 

Air  required  to  burn  1  unit  to  CO      .      .  5-797 
Oxygen    „         „         1     „     „     ,,       .  1-334 

1     ,,     „  C02    .      .  2-667 

Air  „         „         1     „     „  CO2    .      .  11-594 

Temperature  of  combustion  to  CO2 

In  air 2,753°C.  =4,988°F. 

In  oxygen 10,226°C.  =18,440°F. 

Heat  of  combustion  to  CO 

per  pound 4,415  B.Th.U.  =  1,112  cal. 

per  kilo 2,453  cal.  =9,733  B.Th.U. 

Weight  of  vapour  per  cubic  metre  (ideal)       1-072  k.  =0-06696  per  cubic 

foot. 

The  atomic  weight  of  carbon  being  12  and  that  of  oxygen  16, 
the  formula  for  carbon  monoxide  =  CO  tells  that  there  are  12 
parts  of  weight  by  carbon  in  each  28  parts  of  the  gas.  Hence 
1  pound  of  carbon  unites  with  Impounds  of  oxygen  to  produce 
2J  pounds  of  gas. 

When  burned  to  dioxide  =  C02  there  are  12  parts  of  carbon 
to  each  32  parts  of  oxygen,  and  1  part  of  carbon  unites  with 
2 1  parts  of  oxygen  to  produce  3f  parts  of  gas. 

As  oxygen  is  not  available  for  combustion  except  in  the  form 
of  air,  and  as  it  is  not  desired  to  produce  CO,  the  essential 
figures  to  remember  are  that  eachunit  weight  of  carbon  demands 
a  minimum  of  nearly  11-6  units  of  air. 

In  the  foregoing  table  the  temperatures  are  those  calculated 
on  the  assumption  that  the  specific  heat  of  the  gases  produced 
remains  the  same  at  all  temperatures  and  that  combustion  is 
complete.  Neither  assumption  represents  actual  facts,  for  the 
process,  of  combustion  is  delayed  as  temperature  rises,  and 
even  if  it  were  not,  the  specific  heat  increases  and  holds  back 
the  temperature.  Since  in  practice  there  are  so  many  effects 
of  dilution,  the  calculation  of  total  heat  can  be  correctly  done 
on  a  basis  of  constant  specific  heat.  If  a  final  temperature  of 
great  intensity  is  found,  a  correction  can  always  be  applied 
after  all  calculation  has  been  made. 


COMBUSTIBLES  AND  SUPPORTERS  81 

The  various  figures  given  in  this  book  differ  somewhat  from 
many  previously  accepted  figures,  owing  to  the  progress  of  the 
science  of  thermo-chemistry.  The  figures  given  herein  are 
those  given  by  Berthelot  in  his  work,  Thermochimie,  1897. 

Carbon  burned  to  CO  or  directly  to  C02  does  so  with  simple 
incandescence.  No  flame  is  produced.  Carbonic  oxide  =  CO, 
however,  if  formed  by  the  burning  of  carbon  with  insufficient 
air,  will  burn  with  a  blue  flame  if  provided  with  air. 

The  hydrocarbon  gases  burn  with  a  reddish,  a  yellow,  or  a 
white  flame,  according  to  surroundings  and  temperature,  the 
flame  consisting  of  glowing  carbon  in  an  atmosphere  of  hot  gas. 

Hydrogen. 

Hydrogen  shares  with  carbon  the  monopoly  of  the  term  fuel, 
for  there  are  no  commercial  fuels  except  carbon  and  hydrogen 
or  their  joint  compounds.  Hydrogen  is  a  gas.  Its  atomic 
weight  is  1,  and  being  the  lightest  known  element,  it  serves 
as  the  unit  of  atomic  comparison. 

Its  physical  and  other  properties  are  as  follows — 

Atomic  weight  and  density    ....    1 

Specific  heat.     Constant  vol 24146 

„          ,,  „         pressure      .      .   3410 

Weight  per  litre 0-08961  grams  =0-000089  k. 

„         „    cubic  foot 0-00559  pound  =  0-002536  k. 

Cubic  feet  per  pound 178-83=5,063-4  litres. 

Litres  per  kilogram 11,160  =  394-15  cubic  feet. 

Heat  of  combustion  per  kilo.  }  (  34,500  cal.  =  136,900  B.Th.U. 

pound        !ToO°C.  |    62, 100  B.Th.U.  =15,650  cal. 
cubic  foot  I  =32°F.  1    347  B.Th.U.  =8745  cal. 
»  „         litre  I  3-091  cal.  =  12-264  B.Th.U. 

Specific  gravity,  water  =  1       ....   0-0714  when  liquefied. 

Point  of  vaporization 33°  abs.  C.  =60  abs.  F. 

„      freezing  or  liquefaction  .      .      .    16-7°  abs.  C.  =30°  abs.  F. 
Temperature  of  combustion — 

(nominal)  in  oxygen       .      6,762°C.  =12,202°F. 

air.      .      .     2,513°C.=4,554°F. 
Ratio  of  air  required  to  burn  1  unit  weight   34-785 
„  „  „     1  unit  vol.      .  2-39 

>,  „  „     oxygen  weight    .       8-00 

»  t,  ,,     oxygen  vol.    .      .        0-50 

Heat  of  combustion  per  kilo,  (result  in 

vapour) 29,150  cal.  =115,434  B.Th.U, 

Heat  of  combustion  per  pound  (result  in 

vapour) 52,290  B.Th.U.  =  13,177  cal. 

The  heat  of  combustion  of  hydrogen  is  62,100  B.Th.U.  per 
pound.  This  assumes  that  the  products  of  combustion  are 
rejected  in  a  liquid  state.  In  furnace  work,  however,  the  gases 
of  combustion  always  leave  at  temperatures  above  100°C., 


82  LIQUID  FUEL  AND  ITS  APPARATUS 

and  consequently  the  gases  carry  off  with  them  the  latent  heat 
of  evaporation.  This  reduces  the  available  heat  to  52,290 
B.Th.U  per  pound,  or  29,150  cal.  per  kilogram,  or  say  293 
B.  Th.U.  per  cubic  foot  and  2-612  cal.  per  litre.  This  fact  must 
be  borne  in  mind  when  calculating  results. 

SMOKE  PRODUCTION. — Hydrogen  ignites  at  a  temperature 
below  that  necessary  to  ignite  carbon.  Its  affinity  for  oxygen 
is  greater  and,  in  presence  of  an  insufficient  supply  of  air,  the 
hydrogen  of  a  hydrocarbon  fuel  will  first  secure  its  share  of 
oxygen  and  the  carbon  will  appear  as  soot.  Sudden  cooling 
of  a  hot  hydrocarbon  gas  is  also  said  to  produce  soot,  but  it  is 
questionable  if  soot  is  really  produced  without  a  certain  amount 
of  combustion  of  the  hydrogen. 

The  following  table  gives  the  temperature  of  ignition  of  a  few 
of  the  hydrocarbon  gases,  according  to  Mayer  and  Munch — 


CH, 

667°C. 

1,232°F. 

Ethane  ......... 

C2H4 

616°C. 

1,141°F. 

547°C. 

1,017°F. 

580°C. 

1,076°F. 

504°C. 

1,004°F. 

Hydrogen  burns  with  a  transparent  blue  flame.  Its  com- 
pounds with  carbon  burn  with  a  light-giving  flame  consisting  of 
incandescent  carbon  particles  carried  in  an  atmosphere  of  gas. 

These  hydrocarbons  are  exceedingly  numerous,  and  range 
from  gases  of  small  density  through  every  shade  of  liquid  to 
solids  like  naphthalene  and  paraffin  wax. 

The  percentage  of  carbon  and  hydrogen  in  a  petroleum  of 
any  degree  of  refinement  does  not  vary  far  from  84  of  carbon 
and  16  of  hydrogen,  corresponding  with  a  mean  formula  of 


Air. 

Oxygen  being  necessary  for  combustion,  there  is  only  one 
source  whence  it  can  be  obtained  in  large  quantity,  viz.,  the 
atmosphere. 

The  atmosphere  contains  by  volume  — 

20-84  vols.  of  oxygen    )      ,  .      ,   ,      „« 
79-16     „     „   nitrogen  jrs 

There  are  also  small  quantities  of  other  gases,  the  principal 
of  which  is  carbon  dioxide,  C02,  present  to  the  extent  of  only 
0-0004,  and  negligible  for  present  purposes. 


COMBUSTIBLES  AND  SUPPORTERS  83 

By  weight  the  atmosphere  contains  — 


The  mean  atmospheric  pressure  at  sea-level  is  assumed  by 
Rankine  to  be  14-704  pounds  per  square  inch,  at  a  temperature 
of  32°F.  —  0°C.  The  mercury  barometer  then  stands  at 
29-922  inches.  At  this  pressure  water  boils  at  212°F.  =  100°C. 
The  metrical  atmosphere  also  measured  at  0°C.  is  760  mm. 
of  mercury  column  =  29-922  inches.  At  the  ordinary  tem- 
perature of  57-8°F.  the  mercury  barometer  of  30"  =  I  atmo- 
sphere, and  at  all  ordinary  temperatures  and  for  purposes  of 
steam  engineering  it  may  be  called  30  inches. 

Expressed  in  metric  measures,  one  atmosphere  is  1-0333 
kilos  per  square  centimetre  at  Paris. 

A  mercury  column  giving  14-704  at  London  will  give  14-6967 
=  1-0333  kilos  at  Paris  and  14-686  at  New  York. 

The  pressure  and  density  of  the  atmosphere  varies  with  the 
elevation   above   sea   level,    and   may   be   thus   calculated  — 
H  =  60,000  (1-477-log  R),  where 
R  is  the  elevation  in  feet  above  sea  level  ; 
H  is  the  barometric  height  in  inches  at  elevation  R,  and  1-477 
—  log  30. 

Hi^h  elevation  requires  consideration  in  regard  to  the  relative 
volume  of  air  for  furnace  supply. 

Air  at  all  temperatures  for  purposes  of  furnace  work  behaves 
as  a  perfect  gas. 

The  weight  of  a  cubic  foot  of  dry  air  at  62°F.  is  532-5  grains. 
If  saturated  with  moisture  the  weight  is  529  grains.  The 
specific  gravity  of  air  is  819  times  less  than  water,  and  one 
pound  of  air  measures  13-146  cubic  feet  at  62°F. 

The  standard  barometric  pressure  of  1  atmosphere  or  14-6967 
pound  per  square  inch  at  Paris  =  1-0333  k.  per  cm.  is  curiously 
approximate  to  1  k.  per  cm2.  or  to  14-21  per  square  inch. 

Approximately  1  atmosphere  is  equal  to  a  pressure  of  1  k. 
per  square  centimetre. 

The  density  of  air  relative  to  hydrogen  is  14-44,  its  specific 
heat  is  0-2375  at  constant  pressure,  and  0-1686  at  constant 
volume.  One  pound  of  air  measures  12-385  cubic  feet  at  0°C. 
=32°F.,  and  1  cubic  foot  weighs  0-08073  pound.  One  litre  of 
air  weighs  1-292743  grams  at  0°C.  and  760  mm. 

Oxygen. 

Oxygen  is  the  active  constituent  of  the  atmosphere  in  pro- 
moting combustion.  It  combines  with  most  elements  to  form 


84  LIQUID  FUEL  AND  ITS  APPAEATUS 

oxides  with  evolution  of  heat.  The  atomic  weight  of  oxygen 
is  16  and  it  forms  one  stable  oxide  with  hydrogen  —  H20  (see 
Water)  and  two  oxides  with  carbon,  viz. — 

(1)  Carbon    monoxide    or    carbonic     oxide  =  CO,    which 

contains  12  by  weight  of  carbon  and  16  by  weight 
of  oxygen,  and 

(2)  Carbonic  acid  or  carbon  dioxide  =  C02,  containing   12 

by  weight  of  carbon  to  32  of  oxygen. 

The  density  of  oxygen  is  16  ;  its  weight  per  cubic  foot  is 
0-08926  pound  at  0°C.  =  32°F.  and  11-203  cubic  feet  weigh  one 
pound. 

Its  specific  heat  at  constant  pressure  is  0-217  and  at  constant 
volume  0-1548.  One  litre  of  oxygen  at  0°C.  and  760  mm. 
weighs  1-4293  grams. 

Nitrogen. 

This  gas  constitutes  about  four-fifths  of  the  atmosphere. 
It  is  a  colourless  gas  and  very  inert.  It  does  not  support  com- 
bustion, but  acts  by  dilution  to  restrain  its  intensity  and  to 
reduce  the  temperature. 

Its  density  is  14,  specific  heat  =  0-244  at  constant  pressure, 
and  0-173  at  constant  volume.  It  weighs  0-07845  per  cubic 
foot  and  1  pound  equals  12-763  cubic  feet.  One  litre  of  nitrogen 
weighs  1-2505  grams  at  0°C.  and  960  mm. 

The  weight  of  nitrogen  in  the  atmosphere  is  3-32  times  that 
of  oxygen.  It  is,  therefore,  the  cause  of  much  dilution  of  the 
products  of  a  furnace,  and  reduces  the  theoretical  temperature 
of  combustion  to  a  figure  much  below  that  of  combustion  in 
oxygen. 

WATER  AND  STEAM. 

Steam  is  produced  by  heating  water  to  such  a  temperature 
that  the  elasticity  of  the  water  vapour  becomes  greater  than 
the  superincumbent  air  pressure  of  about  14-7  pounds  per 
square  inch  at  the  level  of  the  sea.  (See  Air.) 

Pure  water  is  not  found  in  nature,  but  is  closely  approximated 
in  sain  caught  on  hill-tops  distant  from  towns,  and  in  streams 
which  flow  off  the  barren  country  associated  with  granitic  rocks, 
the  millstone  grits,  and  certain  other  geological  strata.  Water 
is  an  oxide  of  hydrogen,  and  its  chemical  formula  is  H20.  It 
consists  of  2  parts  by  weight  of  hydrogen  to  16  parts  of  oxygen, 
and  it  is  produced  when  hydrogen  is  burned,  the  combustion 
setting  free  a  large  amount  of  heat.  (See  Hydrogen.) 

Water  is  used  as  the  unit  point  in  many  physical  data.  The 
specific  gravity  of  all  other  substances  is  referred  to  that  of 


COMBUSTIBLES  AND  SUPPORTERS 


85 


water  as  unity.  So  also  is  the  specific  heat  of  all  other  sub- 
stances, and  excepting  hydrogen,  the  specific  heat  of  water  is 
the  highest  of  any  known  body.  The  amount  of  heat  necessary 
to  raise  the  temperature  of  1  kilogram  of  water  from  0°C.  to 
1°C.  is  called  the  great  calorie  or  simply  the  calorie,  the  little 
calorie  having  reference  to  the  weight  of  one  gram  only,  and 
being  employed  by  chemists  and  physicists. 

Similarly  the  heat  necessary  to  raise  the  temperature  of 
one  pound  of  water  from  32°F.  to  33°F.  is  called  the  British 
Thermal  Unit  or  B.Th.U.  Thus  1  calorie  =  3-9683  B.Th.U. 
and  1  B.Th.U.  =  0-252  calorie. 


Weight. 

One  gallon  of  pure  distilled  water  at  62°F.  weighs  10  pounds 
by  Act  of  Parliament.  The  American  or  old  wine  gallon 
weighs  8J  pounds  and  measures  231  cubic  inches,  as  com- 
pared with  the  British  Imperial  10  Ib.  gallon  of  277-479  cubic 
inches  (Chaney).  One  cubic  decimetre  of  water  or  1  litre 
weighs,  by  law,  1  kilogram,  the  kilo,  being  2-204  pounds. 
Thus  1,000  k.  weigh  very  nearly  1  ton. 

A  column  of  water  1  foot  high  exerts  a  pressure  at  the  base 
of  0-434  pounds  per  square  inch.  Thus  a  pressure  of  1  pound 
per  square  inch  represents  a  column  of  2-3  feet.  Hence  an 
atmosphere  of  pressure  is  equivalent  to  33-8  feet  of  water 
column. 

Compressibility. 

Water  is  nearly  incompressible,  the  coefficient  at  0°C.  — 
32°F.  being  -000052,  and  at  nearly  53°C.  =  127°F.  =  0-0000441. 
It  is  thus  negligible. 

Expansion. 

Water  changes  its  volume  with  change  of  temperature,  but 
not  to  an  amount  that  is  of  serious  account  in  steam  engineering. 


Temp. 

Weight. 

Temp. 

Weight. 

Temp. 

Weight. 

212°F. 
250 
300 

59-71 

58-81 
57-26 

350° 
400 
450 

55-52 
53-64 
50-66 

500° 
550 
62 

49-61 
47-52 
62-2786 

102 

62-00 

158 

61-00 

203 

60-00 

The  foregoing  table  gives  the  weight  per  cubic  foot  of  water 


86 


LIQUID  FUEL  AND  ITS  APPARATUS 


at  various  temperatures,  showing  that  the  maximum  expansion 
in  the  open  air  does  not  reach  5  per  cent. 

Water  attains  its  maximum  density  at  4°C.  =39-l°F. 

It  becomes  solid  at  a  temperature  of  0°C.  =  32°F.,  the  freez- 
ing point  of  water  being  employed  in  fact  as  the  0°  of  the 
Centigrade  thermometers. 

Ice  has  a  specific  gravity  of  0«922  and  a  specific  heat  of  0-504. 
To  reduce  1  pound  of  ice  at  32°F.  —  0°C.  to  water  also  at 
32°F.  requires  142  B.Th.U.  =  35-78  calories.  The  latent 
heat  of  water  is  thus  said  to  be  35-78  calories  or  142  B.Th.U. 
per  pound,  or  78*86  calories  per  kilogram. 


Specific  Heat. 

The  specific  heat  of  water,  called  1-00  at  0°C.  —  32°F.,  is 
not  uniform,  but  increases  slightly  with  increase  of  temperature, 
as  per  the  following  table  : — 


Temp.  F. 

Specific  Heat. 

Temp.  F. 

Specific  Heat. 

32° 

•0000 

248° 

1-0177 

50 

•0005 

266 

1-0204 

68 

•0012 

284 

1-0232 

86 

•0020 

302 

1-0262 

104 

•0030 

320 

1-0294 

122 

•0042 

338 

•0328 

140 

•0056 

356       . 

•0364 

158 

•0072 

374 

•0407 

176 

•0089 

394 

•0440 

194 

•0109 

410 

•0481 

212 

•0130 

428 

1-0524 

230 

•0153 

446 

1-0568 

As  at  the  above  temperature  the  bulk  of  water  is  increased 
in  a  much  greater  ratio  than  the  specific  heat,  the  total  heat 
per  cubic  foot  will  decrease  somewhat  with  rise  of  temperature. 

As  the  total  heat  contained  in  one  pound  of  steam  measured 
from  32°F.  is  nearly  1,200  B.Th.U.,  this  amount  of  heat  is 
more  or  less  thrown  away  when  steam  is  used  to  atomize  liquid 
fuel.  The  gases  never  leave  a  furnace  below  212°F.,  and  every 
pound  of  steam  carries  off  its  load  of  967  units  of  latent  heat 
to  the  chimney.  Air  being  already  a  gas,  and  necessary  to 
combustion,  causes  no  loss  in  this  manner,  but  it  requires 
power  to  compress  air,  and  some  steam  is  thereby  used,  but, 
especially  at  sea,  such  steam  can  be  condensed  and  does  not 
therefore  lead  to  a  loss  of  fresh  water.  No  extra  work  is 


COMBUSTIBLES  AND   SUPPORTERS  87 

thrown  upon  the  evaporation  plant.  Water  may  be  split  up 
by  heat  into  its  two  constituent  gases.  In  this  process  of 
dissociation  or  decomposition  exactly  as  much  heat  is  absorbed 
as  was  produced  by  the  combination  of  the  gases  when  the 
water  was  formed.  This  plain  chemical  fact  is  ignored  by 
those  who  dream  of  steam  as  fuel,  and  imagine  that  steam  jets 
introduced  into  a  furnace  will  decompose  and  burn  with  any 
effect  in  increasing  the  total  heat  production  of  the  furnace. 
Steam  thus  employed  is  useful  as  a  mechanical  draught  pro- 
ducer only,  or  there  may  be  some  truth  that  hydrocarbons 
burn  better  in  the  presence  of  moisture.  But  no  further 
claim  is  tenable. 


Useful  Figures. 

In  the  calculations  of  the  steam  engineer  it  is  convenient  to 
remember  that  the  square  of  the  diameter  of  a  pipe  or  a  pump 
barrel  gives  the  weight  of  water  in  a  yard  length  of  pipe.  Thus 
a  six-inch  pipe  holds  36  pounds  or  3*6  gallons  per  yard.  Again, 
1  pound  of  coal  should  evaporate  1  gallon  of  water  ;  1  gallon 
of  water  will  give  steam  to  work  in  the  best  engine  yet  made 
at  the  rate  of  1  h.p.  hour.  Two  gallons  will  serve  an  ordinary 
compound  engine  per  h.p.  hour,  and  3  gallons  a  good  non-con- 
densing engine  for  each  h.p.  hour.  Approximately,  too,  1,000 
B.Th.U.  generated  represents  one  pound  of  steam,  so  that  the 
number  of  thousands  of  units  capacity  of  a  pound  of  fuel 
represents  the  theoretical  evaporation  in  pounds  of  water. 


Solubility  of  Salts. 

As  a  rule  this  increases  with  the  temperature,  but  at  a  slow 
rate,  except  for  sodium  chloride  and  a  few  other  exceptions. 
For  the  sulphates  of  magnesium  and  potassium  and  the  chlorides 
of  barium  and  of  potassium,  solubility  is  proportionate  to  the 
increase  of  temperature. 

With  sulphate  of  soda  the  solubility  first  increases  and  then 
falls  off  again. 

The  solubility  of  calcium  sulphate  decreases  with  tempera- 
ture. 

The  following  table  gives  the  solubility  of  a  few  salts  at  various 
temperatures  in  parts  per  100. 

The  solubility  at  212°F.  is  really  at  a  higher  temperature, 
being  the  solubility  at  boiling  point,  which  is  always  raised 
slightly  by  the  solution  of  a  salt. 


'88 


LIQUID  FUEL  AND  ITS  APPARATUS 


Temperature. 

32°F. 

70°F. 

212°F. 

Calcium  chloride      .            * 
Magnesium  sulphate 
Potassium  carbonate 
„          chlorate 
„           chloride 

400-0 
24-7 
100-0 
3-33 
29-21 
13-32 

35-0 

80-0 
8-0 
34-0 
30-0 

130-0 

60-0 
60-0 
240-0 

„           sulphate      .... 
Sodium  carbonate               ... 

6-97 

12-0 
21-7 

26-0 
45-1 

,,       bicarbonate      .... 

6-9 
35-5 

9-6 
36-0 

39-6 

5-02 

22-0 

42-6 

Barium  chloride      
Calcium  carbonate  

35-0 
•0036 
•23 

60-0 
•21 

Magnesium  chloride      .... 
„           carbonate  .... 

200-0 
•02 

— 

400-0 

Sea  Water. 

Sea  water  contains  38  parts  per  1,000  of  dissolved  matter  ; 
of  this  from  25  to  28  parts  are  common  salt,  NaCl. 

The  Black  Sea  contains  only  17-7  parts,  the  Caspian  Sea  14»0, 
and  the  Baltic  6-7,  owing  to  the  large  freshwater  rivers  which 
flow  into  them.  The  other  salts  of  sea  water  are  magnesium 
chloride,  calcium  sulphate,  magnesium  sulphate,  potassium 
sulphate  and  chloride,  bromide  of  soda,  the  carbonates  of  lime 
and  magnesia,  and  traces  of  other  salts  and  organic  substances. 

Hardness. 

By  this  term  is  meant  1  grain  per  gallon  of  lime  carbonate, 
CaC03 .  Temporary  hardness  is  that  which  can  be  reduced  by 
boiling.  Permanent  hardness  is  not  reduced  by  boiling. 
Water  is  softened  by  chemical  means.1 

Pipes. 

The  ordinary  velocity  of  flow  in  water  in  pipes  may  be  taken 
at  72  inches  per  second.  This  velocity  is  to  be  reduced  1  inch 
per  second  for  each  20  pounds  pressure.  Thus  in  feed  pipes 
at  160  pounds  pressure,  the  velocity  will  be  72  —  8  =  64  inches. 
Practical  considerations  demand,  except  where  several  boilers 
are  fed  through  one  pipe,  that  the  pipes  should  be  much  larger 
than  would  give  such  a  velocity  in  many  cases. 

1  See  Water-Softening  and  Treatment,  by  the  Author ;  Constable  & 
Co.  See  also  Liquid  Fuel  and  its  Combustion,  by  the  Author  ; 
Constable  &  Co. 


COMBUSTIBLES  AND  SUPPORTERS  89 

Pipes  less  than  If  inches  are  rarely  advisable  for  feed  pipes, 
and  if  pipes  are  liable  to  be  scaled  up  they  ought  to  be  made 
initially  larger  than  necessary  to  allow  of  a  considerable  deposit 
of  scale  without  unduly  diminishing  their  capacity. 

Useful  Data  regarding  Water. 

1  gallon 10  pounds. 

1  American  gallon      .      .      .  8-321  pounds. 

1  cubic  foot 62-2786  Ib. 

1  gallon 277-479  cubic  inches. 

1  American  gallon      .      .      .  231  cubic  inches. 

1  litre 2-204  pounds. 

1  foot  column       ....  0-434  per  square  inch. 

1  pound  per  square  inch      .  2-304  feet  head. 

1  gallon 0-1606  cubic  feet. 

1  pound 0-01606      „ 

1  cubic  foot 0-0278  ton. 

1  ton 35-97  cubic  feet. 

(Diameter  of  pipe  in  inches)2  Pounds    per    yard    nearly    of 

water  contents. 

1°C.  per  kilogram.      ...  1  calorie. 

1°F.  per  pound     ....  1  B.Tb.U. 

Specific  heat  at  0°C.        .      .  1-00. 

;,     Ice   ....  0  504. 

Specific  gravity  at  0°C.  .      .  1-000. 

„        Ice    ...  0-922. 

1  atmosphere         .     .     .     .  33-8  feet   of  water. 

One  pound  of  oil  requires  about  15  pounds  of  air  for  its 
chemical  combustion,  or  about  207  cubic  feet. 

Approximately  this  is  2,000  cubic  feet  of  air  per  gallon  of 
oil/ 


CHAPTER    VI 

CALORIFIC   AND    OTHER   UNITS 

Thermo-Chemistry. 

THE  subject  will  only  admit  of  slight  treatment  in  a  work 
of  this  description.  It  has  been  exhaustively  treated 
by  Berthelot,  especially  in  his  Thermochimie  of  1897  ;  therein 
he  gives  the  thermal  equivalent  of  almost  all  known  hydrocarbons 
and  other  elements  and  compounds.  When  the  calorific  cap- 
acity of  a  fuel  is  tested  it  will  often  be  found  to  depart  from 
expectation.  Two  fuels  may  have  the  same  composition,  yet 
produce  very  different  effects.  Thus  acetylene  and  benzene 
have  exactly  the  same  ratio  of  hydrogen  to  carbon  in  their 
composition,  their  formula  being  C2H2  and  C6H6  but  their  atoms 
are  differently  put  together,  and  they  produce  very  different 
amounts  of  heat  when  burned.  Acetylene  is  very  much  more 
endo thermic  than  benzene,  that  is  to  say,  it  actually  absorbs 
heat  when  first  compounded,  and  this  latent  heat  adds  to  its 
calorific  output  when  burned.  Benzene  and  ethylene  are 
also  endo  thermic,  but  the  other  fuel  hydrocarbons  and  alcohol 
are  exothermic,  and  having  given  out  heat  when  formed  they 
give  out  correspondingly  less  when  destroyed  by  combustion. 
Thermo-chemistry  teaches  us  to  consider  all  substances  from  a 
monistic  point  of  view,  seeing  in  every  gas  latent  heat  to 
preserve  it  as  a  gas,  without  which  heat  it  would  fall  to  the  state 
of  a  liquid.  Similarly,  we  recognize  that  latent  heat  prevents 
liquids  becoming  solid. 

We  realize  that  the  conversion  of  solid  coal  into  gas,  such 
as  occurs  when  coal  is  burned,  demands  an  enormous  heat 
absorption.  Thus  it  is  that  the  first  oxidation  of  solid  carbon 
to  monoxide  develops  less  than  half  the  heat  of  the  second  oxi- 
dation. The  same  or  even  more  heat  is  developed  by  the  first 
oxidation,  but  disappears  in  changing  the  solid  carbon  and 
solid  hydrocarbons  into  gas.  We  are  enabled  to  appreciate 
the  difficulties  that  stand  in  the  way  of  perfect  combustion 
of  bituminous  fuels,  when  we  perceive  the  heat  absorption  of 
the  gasification  they  endure  before  they  burn.  Thermo-chemis- 

90 


CALORIFIC  AND  OTHEB  UNITS  91 

try  points  out  why  the  calorific  capacity  of  liquid  and  of  gaseous 
fuels  is  better  than  of  solid  fuels  ;  it  teaches  us  to  study  the 
phenomena  of  specific  heat,  and  helps  us  to  understand  and 
account  for  an  infinite  variety  of  apparent  inconsistencies 
and  to  clear  away  the  mists  from  our  earlier  views.  As,  how- 
ever, in  engineering  we  can  only  deal  with  approximations, 
it  is  sufficient  for  ordinary  purposes  to  base  most  calculations 
on  approximations,  and  it  is  useful  to  be  able  to  calculate  the 
approximate  expectation  of  calorific  capacity  of  a  fuel  of  any 
type.  The  formula  of  the  French  chemist  Dulong  may  still 
be  employed  as  substantially  accurate.  It  is — 

Calories  =  a  =  8,080C  +  34,500(H  -  £)  where  C  =  weight 
of  carbon,  H  =  weight  of  hydrogen  and  0  =  weight  of  oxygen 
in  1  kilo,  of  the  fuel;  or,  if  expressed  in  British  Thermal  Units, 
B.Th.U.  =  x  —  14,500C  +  62,100(H  -  f ),  where  x  —  the 
thermal  units,  C  =  the  weight  of  carbon,  H  =  the  weight  of 
hydrogen,  and  0  =  the  weight  of  oxygen  in  one  pound  of  the 
fuel. 

The  Verein  Deutscher  Ingenieure  use  a  modified  formula — 

x  =  8,100C  +  29,000(H  —  £)  +  2,500S  —  600E,  thus  allow- 
ing for  the  sulphur  and  for  the  hygroscopic  water  and  for  the 
fact  that  the  hydrogen  products  are  produced  as  steam. 

Mahler  found  an  average  of  44  fuels  as  follows — 

_  8,140C  +  34,500H  -  3,000(0  +  N)*; 

100 

which  in  B.Th.U.  becomes  when  simplified — 
x  =  200-5C  +  675H  -  5,400. 

Calculation  has  now  given  way  to  actual  measurement  of  a 
sample  in  the  Berthelot  bomb  or  other  form  of  calorimeter. 

We  learn  from  thermo-chemistry  why  it  is  that  the  latent 
heat  of  steam  diminishes  with  higher  pressure,  realizing  that 
the  difference  is  due  to  the  absence  of  performance  of  external 
work. 

A  few  of  the  leading  particulars  referring  to  the  gases  most 
related  to  power  engineering  are  re-tabulated  in  Table  5  from 
the  author's  more  extended  table  in  Kempe's  Year  Book. 

As  a  science  thermo-chemistry  recognizes  no  fuel  as  such. 
It  has  regard  merely  to  the  heat  effects  of  chemical  combi- 
nation. Combustion  is  usually  restricted  to  carbon  and  hydro- 
gen, simply  because  these  are  the  two  substances  we  find  in 
Nature  on  a  sufficiently  large  scale  to  burn  by  means  of  the 
atmospheric  oxygen.  Both  produce  harmless  gases,  namely, 
steam  and  carbonic  acid.  Neither  will  support  life,  but  they 
are  not  poisonous. 


92  LIQUID  FUEL  AND  ITS  APPARATUS 

By  aid  of  thermo-chemical  researches  we  learn  that  the 
various  hydrocarbons  have  either  absorbed  or  given  off  heat 
when  they  combined.  If  the  former,  they  are  said  to  be  endo- 
thermic,  if  the  latter  exothermic.  We  learn  to  make  allowance 
for  the  different  states  of  fuel,  and  to  realize  that  a  gas  ought 
to  be  superior  to  the  same  relative  proportions  of  liquid  fuel, 
and  this  again  to  solid  fuels.  But  methane,  CH4,  is  a  gas,  and 
yet  it  producess  when  burned  an  amount  of  heat  less  than  it 
ought  to  produce,  seeing  that  its  hydrogen  is  still  gaseous  and 
its  carbon  is  also  gaseous.  Instead  of  about  14,728  units  of 
heat,  it  produces  13,343  units  only,  despite  the  benefit  of 
vaporization  of  its  carbon. 

The  explanation  is  that  when  its  elements  combined  they 
gave  out  actually  more  heat  than  was  necessary  to  vaporize 
the  carbon,  and  the  excess  of  heat  was  dissipated  at  the  time, 
and  before  methane  can  burn  with  oxygen,  its  constituents 
must  be  separated  by  means  of  heat.  The  heat  necessary  to 
do  this  reduces  the  heat  of  combustion.  The  different  behaviour 
of  acetylene  arises  from  its  absorption  of  heat  in  formation, 
such  heat  becoming  apparent  when  the  gas  is  burned. 

Heat. 

We  do  not  know  what  heat  is,  but  we  know  its  effects,  and  we 
assume  it  to  consist  in  atomic  or  molecular  vibrations. 

The  effects  of  heat,  as  they  are  apparent  to  our  senses  or  to 
our  reasoning  powers,  are  variously  named.  First  may  be 
placed  temperature.  When  a  body  is  hot  it  can  communicate 
heat  to  bodies  at  a  less  temperature.  Temperature  and  quan- 
tity of  heat  have  no  particular  relation  to  each  other.  A  pound 
of  lead  may  be  hotter  or  have  a  higher  temperature  than  a  pound 
of  iron  or  of  water,  and  may  be  able  to  part  with  heat  to  those 
bodies.  Yet  it  may  possess  much  less  quantity  of  heat,  because 
lead  has  a  lower  specific  heat. 

The  same  substance  in  two  different  states  at  the  same  tem- 
perature, as  ice  at  32°  and  water  at  32°,  possesses  a  different 
amount  of  heat  in  these  two  states.  The  difference  is  expressed 
as  latent  heat,  and  quantity  of  heat  generally  is  expressed  as 
units  of  heat,  and  we  speak  of  the  heat  of  combustion  and  the 
mechanical  equivalent  of  heat,  and  must  therefore  define  all 
these. 

Temperature. 

The  boiling  point  at  which  the  212°  of  the  Fahrenheit  ther- 
mometer is  fixed  is  that  of  pure  water  under  the  mean  atmo- 


CALORIFIC  AND   OTHER  UNITS  93 

spheric  pressure  of  14-7  pounds  per  square  inch.  The  Centigrade 
thermometer  is  marked  zero  at  the  temperature  of  melting  ice 
and  100°  at  the  boiling  point,  the  atmosphere  being  the  pressure 
of  760  millimetres  of  a  mercury  column.  Thus  1°F.=$-  of  a 
degree  Centigrade.  The  mercury  thermometer  is  available  from 
40°F.  to  600°F.,  and  even  higher  if  the  upper  part  of  the  tube  be 
filled  with  compressed  nitrogen.  For  higher  temperatures  it  is 
necessary  to  employ  pyrometers,  which  act  by  recording  the 
difference  of  expansion  of  diverse  metals  or  the  pressure  of 
heated  air,  or  by  electrical  means.  Metallic  thermometers 
are  not  very  satisfactory.  In  steam  engineering,  temperatures 
are  met  with  from  32°  to  600°F.  in  the  engine-room,  from  350° 
to  3,000°F.  between  the  chimney  and  the  furnace.  By  tem- 
perature is  meant  that  state  of  a  body  due  to  heat,  in  which 
the  said  body  can  transfer  heat  to  other  bodies  of  less  tem- 
perature. Temperature  is  a  heat  effect  apparent  to  the  sense  of 
touch,  and  only  by  temperature  can  heat  be  transferred  from 
one  body  to  another,  and  the  transfer  is  always  from  the  hotter 
body  to  the  less  hot  body.  In  this  way  heat  can  be  transferred 
from  a  body  containing  less  actual  heat  to  one  that  contains 
more  heat.  Thus  a  mass  of  one  pound  of  iron  heated  to  a  tem- 
perature of  132°F.  contains  12-98  heat  units.  A  similar  mass 
of  water  at  a  temperature  of  82°  contains  50  heat  units,  the 
heat  content  being  in  each  case  measured  from  a  datum  of 
32°F.  Yet  if  we  immerse  the  iron  in  the  water,  heat  will  leave 
the  iron  which  contains  so  little  heat  and  will  enter  the  water 
that  contains  so  much  heat,  and  will  raise  the  temperature  of 
the  water.  A  clear  distinction  must  be  made  between  tem- 
perature and  quantity  of  heat.  Temperature  can  be  measured 
by  a  thermometer,  but  specific  heat  can  only  be  ascertained  by 
equalizing  the  temperature  of  the  substance  whose  specific 
heat  is  sought  with  that  of  a  mass  of  water.  The  final  tempera- 
ature  enables  the  specific  heat  of  the  substance  to  be  compared 
with  that  of  water. 

There  are  three  thermometric  scales,  namely — 

The  Celsius  or  Centigrade,  which  divides  the  distance  between 
freezing  and  boiling  of  water  at  sea  level  into  100  degrees,  the 
freezing  point  being  0°. 

The  Reaumur  scale,  still  much  used  in  Russia,  divides  the 
same  distance  into  80  parts,  also  starting  from  0°  =  freezing 
point  of  water. 

The  Fahrenheit  scale  divides  the  same  distance  into  180 
parts,  but  starts  the  zero  mark  at  32°  below  freezing.  Hence 
the  boiling  point  is  212°.  It  is  frequently  necessary  to  con- 
vert one  reading  to  another.  The  following  are  the  formulae 


94  LIQUID  FUEL  AND  ITS  APPARATUS 

for  doing  so,  C.,  R.  and  F.  being  the  respective  readings  on 
each  scale. 

To  convert  C.  to  R.— 

C.°  x  |  =  R.° 
To  convert  R.  to  C.— 

R.°  x  £  =  C.° 
To  convert  C.  to  F.— 

(C.°  X  f )  +  32°  =  F.° 
To  convert  F.  to  C.— 

(F.°  -  32°)  x  f  =  C.° 
To  convert  F.  to  R. — 

(F.°  -  32°)  x  |    -  R.° 
To  convert  R.  to  F. — 

(R.°  x  f )  +  32°  =  F.° 

It  is  particularly  necessary  not  to  forget  the  addition  or  sub- 
traction of  the  32°  of  the  Fahrenheit  freezing  point  when  con- 
verting temperatures,  but  it  is  also  necessary  to  remember  not 
to  do  so  when  converting  mere  statements  of  differences  of 
temperature.  Thus  if  water  is  cooled  50°C.,  this  means  it  has 
been  cooled  through  90°F.,  not  through  90°  +  32°.  This  point  is 
often  confused  by  writers  and  leads  to  very  erroneous  statistics. 
By  temperature  we  thus  understand  that  a  body  in  a  certain 
state  is  in  a  certain  condition  of  molecular  vibration.  Different 
bodies  are  differently  affected  by  heat.  Some  bodies  are  placed 
in  the  state  of  molecular  vibration  known  as  temperature  with 
less  heat  than  others.  Thus  water  requires  more  heat  than 
any  other  substance,  excepting  only  hydrogen.  The  relative 
amounts  of  heat  to  place  bodies  in  a  given  state  of  vibration  are 
called  their  capacity  for  heat  or  specific  heat. 

In  Table  VI  are  given  a  few  characteristic  temperatures. 
Furnace  temperatures  can  now  be  measured  by  the  Fery 
radiation  pyrometer.  This  instrument  is  stood  at  any  con- 
venient and  comfortable  distance  from  the  furnace,  and  the 
hottest  of  furnaces  may  thus  easily  be  measured.  The  in- 
strument is  not  exposed  to  high  temperature,  though  it  measures 
this  from  its  distant  standpoint.  It  can  be  obtained,  with 
explanation  of  use,  from  the  Cambridge  Scientific  Instrument  Co. 

Specific  Heat. 

By  specific  heat  is  meant  the  number  of  heat  units  necessary 
to  raise  1  pound  of  a  substance  1°  Fahrenheit,  and  as  water 
has  the  highest  specific  heat  of  any  solid  or  liquid,  it  is  taken 
as  the  basis.  The  specific  heat  of  water  is  measured  at  the 
temperature  of  maximum  density,  39-l°F.,  by  some  writers, 


CALORIFIC  AND   OTHER  UNITS  95 

including  Rankine,  but  32°  is  probably  more  usual.  The 
difference  is  unimportant.  The  specific  heat  of  all  bodies 
increases  slightly  with  increase  of  temperature,  a  fact  due  to 
the  increased  molecular  movement,  and  there  is  often  very 
considerable  difference  between  the  specific  heat  of  the  same 
body  solid  and  liquid,  notably  in  the  case  of  water,  the  specific 
heat  of  ice  being  only  0-504°. 

Since  1  pound  of  water  requires  1  unit  of  heat  to  raise  its 
temperature  1°,  its  specific  heat  is  thus  said  to  be  unity.  All 
other  substances  are  referred  to  water  as  a  basis.  Thus  when 
we  say  that  lead  has  a  specific  heat  of  0-0314,  we  mean  that  to 
heat  a  pound  of  lead  to  a  certain  temperature  only  requires 
about  3  per  cent,  of  the  amount  expressed  in  B.Th.U.  that 
would  be  required  to  raise  the  temperature  of  an  equal  weight 
of  water  by  the  same  amount.  It  is  necessary  to  know  the 
value  of  the  specific  heats  of  brick,  iron,  fuel  and  its  products, 
in  order  to  calculate  pyrometric  effects,  furnace  temperatures, 
etc.  For  the  purpose  Table  VII  of  specific  heats  will  usually 
serve.  More  extended  tables  are  found  in  most  pocket-books. 

Gases  have  two  specific  heats  ;  that  at  constant  volume 
and  that  at  constant  pressure,  the  latter  being  greater  and  due 
to  the  work  done  in  expanding  to  constant  pressure.  Table  VII 
gives  the  specific  heat  of  the  more  usual  gases  met  with  in 
combustion. 

The  specific  heat  of  all  substances  appears  to  increase  with 
heat,  more  especially  in  the  case  of  the  gases.  This  is  not  of 
much  importance  in  boiler  work,  but  is  considerable  in  gas 
engine  research.  In  high  temperature  work  the  increase 
must  be  considered,  but  no  error  is  introduced  by  neglecting 
the  change  when  results  are  finally  stated  at  low  temperatures. 
The  increase  of  specific  heat  with  temperature  is  most  marked 
in  the  case  of  the  more  easily  liquefied  gases. 

Specific  heat,  then,  is  the  relative  amount  of  heat  necessary 
to  give  to  bodies  a  given  temperature.  The  specific  heat  of 
other  bodies  is  stated  as  the  fraction  of  unity  relative  to  water. 
Most  substances  about  a  furnace,  as  fire-brick,  have  a  specific 
heat  of  about  0-2.  The  total  heat  in  a  body  is  the  product  of 
its  mass,  its  temperature  and  its  specific  heat  as  compared 
with  some  substance  at  another  temperature  and  in  the  same 
state  physically.  Thus  ice,  water  and  steam  which  are 
chemically  identical,  differ  in  their  physical  states  and  cannot 
be  so  compared.  The  specific  heat  of  ice  is  only  about  0-504,  and 
that  of  steam  is  0480.  Ice  at  32°F.  may  have  heat  added  to  it 
until  it  becomes  water  at  32°F. 

Water  at  212°F.  will  absorb  heat  and  become  steam  at  212°F. 


96 


LIQUID  FUEL  AND  ITS  APPARATUS 


In  both  these  cases  we  see  no  change  of  temperature  due  to  the 
additional  heat,  but  we  see  a  change  of  physical  condition. 
One  pound  of  ice  has  absorbed  142  B.Th.U.  of  heat  to  enable 
it  to  exist  as  water.  Any  further  heat  then  added  will  increase 
the  temperature  until  212°F.  is  reached.  Then  we  may  add 
966-7  B.Th.U.  to  the  water  with  no  change  of  temperature, 
but  we  get  the  water  in  the  still  higher  physical  state  of  steam. 
In  each  case  the  heat  has  become  hidden  or  latent.  It  is  not 
apparent  as  temperature,  but  is  occupied  in  keeping  the  molecule 
liquid  or  gaseous,  as  the  case  may  be.  Heat  which  thus  disap- 
pears in  changing  the  state  of  a  body  is  termed  latent  heat. 

Latent  Heat. 

Latent  heat  is  thus  the  heat  enquivalent  of  the  changed 
state  of  a  body.  It  is  not  stated,  however,  as  is  specific  heat, 
in  terms  of  the  ratio  to  water,  but  in  actual  heat  units  per  unit 
of  weight,  as  in  calories  per  kilogram  or  B.Th.U.  per  pound. 
Thus  the  latent  heat  of  water  is  said  to  be  142-6,  because  the 
melting  of  1  pound  of  ice  demands  142-6  B.Th.U.  It  is  impor- 
tant to  know  the  latent  heat  of  a  few  substances.  Some  are 
given  in  the  table  below,  those  marked  *  being  hypothetical 
and  not  definitely  determined. 


Per  Pound. 

Per  Kilo. 

B.Th.U. 

Cal. 

Cal. 

B.Th.U. 

Ice  to  water,  both  at  32°F  .  . 
Water  to  steam,  212°F.  .  .  . 
Carbon  to  gas  

142-6 

966 
5,817 
444 
7,320 
521 
6,900 

35-93 
243-3 
1,466 
111-9 
1,845 
131-3 
1,739 

792 
536-4 
3,231 

246-7 
4,066 
289-4 
3,833 

314-3 
2,128 
1,282 
978-4 
16,130 
1,148 
15,210 

Oxvseii  to  eras  *  . 

Hydrogen  to  gas  *  .  .  .  . 
Nitrogen  to  gas  *  

Water  to  gas  (H2O  dissociated)1 

Heat  becomes  latent  not  merely  by  such  a  process  as  actual 
boiling  of  water.  It  becomes  latent  equally  when  water  is 
converted  to  vapour  by  absorption  in  dry  air  :  the  heat  must 
come  from  somewhere  in  such  a  case,  and  it  comes  primarily 
from  the  air  or  from  the  wooden  floor  on  which  water  has  been 
sprinkled  for  cooling  purposes.  If  steam  be  heated  above  its 
saturation  temperature,  it  will  now  only  absorb  about  0-480 
of  a  unit.  Hence  the  specific  heat  of  steam  is  barely  half  that 
of  liquid  water.  After  a  very  considerable  further  addition 
of  heat,  a  point  is  reached  where  the  temperature  again  ceases 
to  rise  ;  but  again  here  is  a  change  of  state.  The  water  is 


solid  condition  in  coal. 


CALORIFIC  AND   OTHER  UNITS  97 

split  up  into  constituent  elements  of  oxygen  and  hydrogen, 
and  one  pound  of  steam  will  absorb  6,900  thermal  units  during 
the  splitting  up  of  its  chemical  affinities,  showing  the  great 
energy  of  chemical  changes,  for  to  melt  ice  requires  142  heat 
units  per  pound  ;  to  vaporize  the  water  requires  966-7  heat 
units,  and  to  decompose  it  demands  6,900.  No  matter  how 
it  occurs  that  a  body  change  its  state,  heat  is  given  out  or 
absorbed.  To  set  free  the  solid  hydrogen  or  solid  water  locked 
up  in  a  piece  of  coal  demands  heat  which  is  rendered  latent. 
Thus  heat  is  rendered  latent  when  carbon  is  vaporized,  and 
when  again  carbon  is  reduced  from  its  state  of  carbonic  acid  gas 
to  the  solid  form  of  wood  by  the  action  of  the  living  forces  of  a 
tree,  the  heat  is  again  set  free  by  the  solidification  of  the  carbon  ; 
but  the  heat  rendered  latent  in  the  decomposition  of  a  body 
is  known  as  the  heat  of  dissociation,  and,  like  latent  heat,  is 
expressed  in  actual  heat  units. 

Dissociation. 

The  heat  absorbed  in  any  process  of  chemical  dissociation 
is  an  exact  equivalent  of  the  heat  which  is  set  free  when  the 
same  substances  combine.  Thus  if  1  pound  of  hydrogen  unite 
with  8  pounds  of  oxygen  to  produce  9  pounds  of  water,  the 
heat  of  combination  is  62,100  B.Th.U.,  and  therefore  the  heat 
of  dissociation  of  water  is  62,100  -^-  9  =  6,900  B.Th.U. 

There  now  remains  to  consider  only  the 

Unit  of  Heat. 

The  unit  of  heat  is  merely  an  arbitrary  measure  of  comparison. 
In  British  measures  it  is  the  amount  of  heat  necessary  to  raise 
the  temperature  of  1  pound  of  water  through  1°F.  at  or  near 
32°F. 

In  the  metric  system  it  is  the  amount  of  heat  necessary  to 
raise  the  temperature  of  1  kilogram  of  water  through  1°C. 

As  1  kilogram  =2-204  pounds  and  1°C.  =£°F.  the  ratio  of 
the  two  units  is  2-204  x  9  -^  5  =  3-968,  the  reciprocal  of  which 
is  0-252. 

The  British  Thermal  Unit  is  written  B.Th.U.,  and  the  metric 
unit  is  called  the  calorie  and  is  written  cal.  Therefore  1  cal.— 
3-968  B.  Th.U.,  and  1  B.Th.U.=  0-252  cal.  For  near  approxi- 
mation the  ratio  of  4  :  1  may  be  employed. 

The  heat  unit  is  employed  to  express  latent  heat  of  com- 
bustion or  of  dissociation. 

It  is  necessary  to  have  a  statement  of  the  relation  of  the  heat 
form  of  energy  and  the  unit  of  mechanical  work. 

G 


98  LIQUID  FUEL  AND  ITS  APPARATUS 

Unit  of  Work. 

The  unit  of  work  is  expressed  in  the  form  of  the  earth's 
attraction. 

For  the  purpose  of  the  engineer  the  attraction  of  the  earth 
is  measured  by  the  pull  exerted  at  sea  level  in  the  latitude  of 
London  upon  a  piece  of  metal  which  is  called  the  pound.  The 
work  done  in  lifting  one  pound  through  a  height  of  one  foot  is  a 
unit  of  work  and  is  called  the  foot  pound.  Heat  and  mechanical 
work  are  mutually  convertible.  Dr.  Joule,  of  Manchester,  by 
the  agitation  of  water  by  means  of  falling  weights,  ascertained 
that  the  unit  of  heat  or  B.Th.U.  is  the  equivalent  of  772  pounds 
raised  one  foot,  or  772  foot  pounds  at  the  latitude  and  elevation 
of  Manchester,  and,  with  very  slight  variation,  of  no  account  in 
engineering,  at  any  spot  on  the  earth's  surface.  Joules'  deter- 
mination of  772  was  made  by  means  of  thermometers  less 
perfect  than  those  now  procurable,  or  his  figure  would  have 
been  778  foot  pounds,  as  since  found  by  Rowland. 

The  mechanical  equivalent  of  772  foot  pounds  per  degree 
Fahrenheit  becomes  1,389*6  foot  pounds  per  degree  Centigrade. 

Expressed  in  terms  metrical  altogether  or  in  kilogram 
Centigrade  units,  the  equivalent  is  3,063-54  foot  pounds  or 
423-55  kilogram  metres. 

Thus  the  calorie  is  423-55  km.  =  3-968  B.Th.U. 

With  the  more  modern  figure  of  778  foot  pounds  =  1  B.Th.U. 
=3,087-3  foot  pounds.  Per  calorie  =  426-84  kilogram  metres, 
so  that  1  B.Th.U.  =107-78  metre  kilograms. 

Weight. 

Like  the  British  pound,  the  kilogram  is  simply  a  piece  of 
metal,  and  work  units  are  done  in  raising  it  against  the  pull  of 
gravity.  Hence  the  kilogram  metre,  whose  relation  to  the  foot 
pound  is  7-231  :  1. 

The  kilogram  is  2-2  pounds  (actually  2-2046212).  The  pound 
is  thus  0-4536  kilos. 

The  metre  or  unit  of  length  is  39  370432  inches,  or  say  3  feet 
3  inches,  and  f-  very  nearly  for  easy  remembrance  and  mental 
calculation. 

Errors  in  converting  units  are  most  likely  to  occur  when  units 
are  compound,  as  when  converting  pounds  per  square  inch  to 
kilos  per  cm.2 

Very  closely  the  English  ton  of  2,240  pounds  resembles  the 
French  tonne  of  1,000  k.  =2,204-6  pounds. 

Also  1  k.  per  linear  metre  is  equal  nearly  to  2  pounds  per 
linear  yard,  and  9  calories  per  cubic  metre  is  very  closely 
1  B.Th.U.  per  cubic  foot. 


CALORIFIC    AND   OTHER   UNITS  99 

Gravity. 

Gravity  —  G  at  Greenwich  is  32-19078  feet  per  second 
acceleration  per  second,  usually  written  32-2  per  sec2. 

The  expression  <\/2G  may  be  approximated  as  8. 
Metrically,  G  =  9  8117  metres  per  second2  at  Greenwich. 
The  true  value  at  any  other  latitude  (L),  in  centimetres  per 
second2  is — 

980-6056-2-5028  Cos2(L)- 0-000003  H, 

where  H  is  the  height  above  sea  level  in  centimetres. 
Other  compound  units  that  are  useful  are  as  follows — 

1  B.Th.U.  per  sq.  ft.  =  2-713  cal.  per  square  metre. 
1         ,,  ,,     pound  =  0-556  cal.  per  kilogram. 

To  find  the  number  of  cubic  feet  of  air  at  62°F.  chemically 
consumed  for  one  pound  of  fuel,  take  the  percentage  of  carbon, 
hydrogen  and  oxygen  in  fuel.  To  the  carbon  add  three  times 
the  hydrogen  and  subtract  four- tenths  of  the  oxygen  and 
multiply  the  remainder  by  1-52.  The  product  is  the  cubic 
feet  of  air  (A). 

Thus  A  =1-52(0  +  3H-0-4  0). 

The  weight  of  air  per  cubic  foot  is  -  — —  pounds,  or  13'  14  cubic 

lo'  14 

feet=  1  Ib. 

The  total  weight  of  gaseous  products  per  pound  of  fuel  is 
found  by  multiplying  the  percentage  of  carbon  by  0-126  and 
that  of  the  hydrogen  by  0-358.  The  sum  gives  the  total  gases 
(W),  thus  W  =0-126  0  +  0-358  H. 

The  total  volume  is  found  by  multiplying  the  carbon 
percentage  by  1-52  and  the  hydrogen  by  5  52  ;  the  sum  of 
these  is  the  total  volume  (V)  in  cubic  feet  at  62°F.,  thus 
V:=  1-520  +  5-52  H. 

The  volume  at  any  other  temperature  (T)  is  V7  = 

v  T  +  461 
523 

THE  CALORIFIC  POWER  OF  FUEL. 
Calorific  Formula. 

Dulong  and  Petit  and  subsequently  Favre  and  Silbermann 
determined  the  calorific  capacity  or  heat  of  combustion  of 
many  substances  with  more  or  less  accuracy.  Dulong  endea- 
voured to  find  a  formula  for  calculating  the  heat  of  combustion 
of  any  fuel  of  which  the  chemical  composition  was  known. 


100          LIQUID  FUEL  AND  ITS  APPARATUS 

The  capacity  given  by  him  to  carbon  was  7,295  calories.  The 
latest  determination  of  Berthelot  is  8,137  and  that  for  hyd- 
rogen is  34,500. 

Dulong's  formula  for  fuel  according  to  its  composition  is, 
with  the  correction  to  modern  coefficients — 

Cal.  =8,137  C  +  34,500  (H-f)  where 

C  is  the  carbon  in  1  kilogram  of  fuel,  and  H  and  0  are  the 
hydrogen  and  oxygen  respectively,  it  being  assumed  that  the 
oxygen  is  already  combined  with  hydrogen  and  that  so  much 
of  the  hydrogen  is  already  useless.  Any  error  would  appear 
to  be  on  the  safe  side,  and  the  formula  assumes  the  return  of 
all  the  gases  to  0°C. 

In  actual  practice,  the  gases  pass  at  a  temperature  of  over 
100°C.,  and  the  water  is  in  the  form  of  vapour,  and  the  calorific 
capacity  of  hydrogen  is  often  taken  as  only  29,150  B.Th.U.,  to 
allow  for  the  heat  absorbed  in  vaporization  of  the  water. 

In  Germany,  Dulong's  formula  is  thus  used  in  the  form — 

Cal.  =  8,100  C  +  29,000  (H-f)  +  2,500S-600W, 

where  S  is  the  sulphur  present,  and  W  is  the  weight  of  hygro- 
scopic water. 

Seeing  that  in  coal  the  hydrogen  is  as  solid  apparently  as  the 
carbon,  it  appears  correct  to  take  something  off  the  co-efficient 
of  hydrogen  to  allow  for  the  heat  absorbed  in  gasifying  it,  and 
in  the  above  formula  the  subtraction  of  150  calories  perhaps 
helps  to  make  this  formula  coincide  very  closely  with  calori- 
metric  results. 

Possibly  also  the  rounding  off  of  the  co-efficient  for  carbon 
from  8,137  to  8,100  helps  to  correct  for  the  vaporization  of  the 
carbon  compounds  which  are  exothermic  when  first  formed, 
and  do  not  give  up  the  full  heat  value  of  their  separate  hydrogen 
and  carbon.  Both  marsh  gas,  CH4,  and  ethane,  C2H6,  give 
out  heat  when  formed  and  require  it  again  when  dissociated, 
and  coal  is  so  complex  a  body,  as  are  also  liquid  fuels,  that  very 
little  positive  knowledge  can  be  assumed  :  it  is  sufficient  to 
know  that  the  formula  last  given  is  a  very  fair  approximation 
to  the  truth. 

The  Calculation  of  Temperatures. 

The  temperature  of  combustion  of  any  substances  depends 
upon  the  calorific  capacity  of  the  burning  material,  the  total 
weights  of  the  products  formed,  and  the  specific  heat  of  the 
products.  The  calculation  of  the  theoretical  temperature  is 
therefore  simple. 


CALORIFIC  AND   OTHEIt,  UNITS^? 

The  specific  heat  of  all  bodies,  and  particularly  of  gases, 
increases  with  temperature,  and  this  reduces  the  temperature 
actually  obtained.  Though  hydrogen  has  so  high  a  calorific 
capacity,  it  does  not  produce  a  specially  high  temperature  as 
compared  with  carbon,  for  in  the  first  place  it  demands  8  times 
its  own  weight  of  oxygen,  and  secondly  the  specific  heat  of  the 
product,  steam  gas,  is  also  high,  viz.,  0479. 

The  calculation  of  temperature  for  hydrogen  burned  with 
oxygen  is  — 

T  =  9 

These  are  temperatures  very  much  in  excess  of  anything 
secured  in  the  laboratory,  which  has  not  reached  3,000°C. 
(even  under  a  pressure  of  10  atmospheres). 

With  air,  however,  the  oxygen  is  accompanied  by  a  weight 
of  nitrogen  3-32  times  its  own  weight,  and  to  burn  1  unit  of 
hydrogen  requires  8  pounds  of  oxygen  and  26-56  of  nitrogen, 
the  specific  heat  of  which  is  0-244.  The  calculation  for  tem- 
perature is  thus  — 


T  =  (9  x  0479)  +656  x  0-244)  =  2>513*C'  =  4'554°F' 

The  calculation  for  carbon  turned  to  carbonic  oxide  is  similarly 
derived  from  the  heat  capacity  =2,453  cal.  The  oxygen 
necessary  is  1J  times  the  weight  of  the  carbon  consumed,  and 
as  the  calorific  effect  of  the  first  oxidation  of  carbon  is  2,453 
calories  per  kilogram,  we  obtain  — 


when  burned  with  oxygen,  the  total  product  being  2-33  k.  of 
carbonic  oxide  of  0-245  sp.  heat.  Then,  with  air  containing 
3  32  times  as  much  nitrogen  as  oxygen,  we  have  —  • 

r  _  2,453  _ 


"(2-333  X  0-245)  +  (1-333  X  3-32  X  0-244) 
=  2,705°F. 

Where  the  amount  of  air  is  in  excess  of  the  chemical  minimum, 
a  further  term  must  be  inserted  in  the  denominator  ;  as  neither 
the  nitrogen  nor  the  oxygen  of  the  excess  air  is  altered,  they 
may  be  considered  together.  The  sp.heat  of  air  is  0-237,  and 
the  weight  per  unit  of  fuel  being  W,  we  have  the  new  term 
in  the  denominator  (W  X  0  237),  and  the  temperature  of  the 
final  product  is  reduced  simply  because  of  the  greater  weight 
of  final  gases  over  which  the  heat  generated  per  unit  of  fuel  is 


102         LIQUID  FUEL  AND  ITS  APPARATUS 

distributed.  In  Table  V  are  given  the  calorific  capacities 
of  the  various  forms  of  carbon  and  of  hydrogen,  together  with 
the  resulting  temperatures  of  combustion  with  a  minimum 
of  oxygen  or  equivalent  air.  The  values  are  given  per  gram, 
litre,  pound  and  cubic  foot  for  combustion  to  carbonic  oxide 
=  CO  and  to  carbonic  acid  =  C02  for  carbon,  and  to  water 
(vapour)  and  water  (liquid)  for  hydrogen. 

These  temperatures  are  not  attained  in  practice.  St.  Glair 
Deville  considers  that  they  are  prevented  from  occurring  by 
the  dissociation  which  is  said  to  occur  at  high  temperatures. 
A  certain  temperature  is  attained  and  further  combustion 
ceases  until  some  of  the  heat  has  been  dispersed,  when  further 
combustion  proceeds.  Berthelot,  while  not  ignoring  dis- 
sociation, is  rather  of  the  opinion  that  the  inability  to  attain 
theoretical  temperature  arises  from  the  proved  increase  of  the 
specific  heat  of  all  bodies,  and  especially  of  gases  at  high  tem- 
peratures. Probably  both  causes  have  effect. 

With  liquid  fuels,  which  contain  so  much  hydrogen,  the 
calorific  capacity  of  the  hydrogen  cannot  exceed  29,100  cals. 
or  52,290  B.Th.U.,  because  the  aqueous  vapour  always  passes 
away  as  vapour. 

One  pound  of  water  vapour  contains — 

1,091-7  +  0-305  (T  -  32°)  B.Th.U.,  where  T  is  the  temperature 

Fahrenheit. 

Similarly  where  T  is  the  temperature  Centigrade  1  kilogram 
contains  606-5  -j-  0-305  T°  calories,  whence  can  be  calculated 
the  heat  lost  where  saturated  steam  is  thrown  away.  But  in  a 
furnace  the  waste  gases  are  much  above  saturation  temperature, 
and  all  vapour  above  212°F.  must  be  calculated  to  absorb  at 
least  0-480  of  a  thermal  unit  or  calorie  per  pound  or  per  kilo- 
gram for  each  degree  Fahrenheit  or  Centigrade  beyond  212°F. 
or  100°C.  respectively. 

In  calculating  furnace  temperatures  there  must  always  be 
added  the  temperature  of  the  atmosphere  to  the  calculated 
temperature,  which  is  based  on  the  datum  of  0°C.  The  usual 
atmospheric  temperature  is  15°C.  =  60°F.  for  convenience,  a 
sufficient  approximation.  The  total  amount  of  water  to  be 
allowed  for  in  any  fuel  sample  is  nine  times  the  weight  of 
hydrogen  in  the  sample  plus  all  the  water.  Water  should  be 
nil  with  liquid  fuel  warmed  sufficiently  to  cause  the  water  to 
separate. 

In  calculations  of  the  hydrocarbon  gases  the  figures  given 
above  are  combined  ;  thus  for  benzene,  C6H6,  the  calorific 
capacity  is  10,052  from  the  gas  or  9,960  cal.  from  the  liquid. 


CALORIFIC  AND   OTHER  UNITS  103 

This  substance  requires  in  all  3-077  times  its  weight  of  oxygen, 
and  produces  3-385  parts  of  CO2  and  0-6923  of  H20,  or  4-077  in 
all. 

The  calculation  for  temperature  is  therefore  — 

9  960 
(0-0923  x  0479)"+  (3-385  x  0-217)  = 

when  burned  in  oxygen. 

With  air  there  is  an  added  weight  of  nitrogen  equal  to  3-077 
X  3-32,  the  specific  heat  of  which  is  0-244. 

This  product,  3-077  x  3-32  x  0-244  is  added  in  the  denomi- 
nator, and  the  resulting  temperature  is  found  to  be  2,798°C. 


Any  excess  of  air  above  that  chemically  necessary  is  then 
allowed  for  by  means  of  the  extra  term  in  the  denominator 
(W  X  0-237),  as  above  explained. 

Relative   Volume  of  Gases  produced  by  Combustion. 

When  a  fuel  contains  carbon  only  the  volume  of  the  gases 
produced  by  perfect  combustion  is  identical  with  the  air  ad- 
mitted to  the  furnace,  for  in  producing  carbon  dioxide  two 
volumes  of  oxygen  produce  two  volumes  of  carbonic  acid,  or 
C  x  02  =  C02,  which,  like  almost  all  compound  gas,  occupies 
two  volumes. 

When  combustion  is  imperfect  and  carbonic  oxide  is  formed, 
the  result  is  C  +  O  —  CO,  or  two  volumes  from  only  one 
volume  of  oxygen,  and  the  waste  gases  exceed  the  volume  of 
air  supplied. 

Sulphur  in  a  fuel  leads  to  no  change  in  volume.  Hydrogen, 
2  volumes,  forms  with  1  volume  of  oxygen  2  volumes  of  gas, 
or  H2  +  O  =  H2O=2  volumes  of  water  vapour.  But  when  flue 
gases  are  collected  the  water  vapour  condenses  and  there  is  a 
diminution  of  volume. 

Each  unit  of  hydrogen  in  fuel  requires  8  units  of  oxygen. 

Expressed  metrically,  1  gram  of  hydrogen  will  consume  8 
grams  of  oxygen.  As  oxygen  weights  1-43  grams  per  litre, 
each  1  gram  of  hydrogen  will  cause  to  disappear  5-6  litres  of 
oxygen  or  nearly  0-2  cubic  feet. 

This  volume  disappears  and  the  total  volume  of  gases  must 
be  increased  by  the  addition  of  the  volume  of  oxygen  destroyed 
by  hydrogen. 

Though  not  of  much  account  in  respect  of  coal,  the  large 
percentage  of  hydrogen  in  liquid  fuel  renders  the  waste  gases, 
when  cooled,  very  much  less  in  volume  than  the  original  volume 
of  air.  Thus  an  ordinary  oil  may  contain  12  per  cent,  of 


104         LIQUID  FUEL  AND  ITS  APPARATUS 

hydrogen,  or  120  grams  per  kilogram.  This  will  destroy  960 
grams  of  oxygen  or  672  litres  for  each  kilogram  of  liquid  fuel. 
In  calculating  the  percentages  of  the  total  gases  this  volume 
of  vapour  must  be  allowed  for.  Per  pound  of  fuel  containing 
say  12  J  per  cent,  of  hydrogen  exactly  one  pound  of  oxygen 
will  be  used  measuring  11-2  cubic  feet.  Thus  should  the 
apparent  volume  of  air  be  260  cubic  feet,  the  actual  volume 
would  be  271-2. 

The  Table  of  gases  (V)  will  be  useful  in  such  calculations. 

Evaporative  Power  of  Fuel. 

The  evaporative  power  of  fuel  is  usually  stated  in  terms  of 
the  water  evaporated  from  and  at,  100°C.=212°F.,  at  which 
temperature  all  the  added  heat  becomes  latent  and  disappears 
at  the  rate  of  537  calories  per  kilogram  of  water,  or  966'  7 
B.Th.U.  per  pound.  The  theoretical  duty  is  thus  obtained 
by  dividing  the  calorific  power  of  the  fuel  by  these  numbers  — 

Hydrogen  should  evaporate      '        =  54*28  times  its  weight 

OO  i 

8  137 
of  water.     Carbon  should  evaporate     '        =  15-15  times,  and 


the  best  coals  have  a  capacity  of  about  15  J  times,  the  highest 
values  corresponding  with  the  highest  proportion  of  hydrogen 
when  this  is  not  neutralized  by  being  already  in  combination 
with  oxygen.  Liquid  fuel  may  run  as  high  as  22  evaporation. 

The  actual  evaporation  secured  will  fall  short  of  the  theoreti- 
cal by  15  per  cent,  in  the  very  best  exceptional  cases  to  30  per 
cent,  in  good  but  heavily  worked  boilers,  the  results  obtained 
depending  upon  the  perfection  of  combustion,  the  avoidance 
of  excessive  air  and  the  proportions  and  condition  of  the  boiler. 
A  good  result  with  coal  is  10J,  which  corresponds  with  about 
15  for  good  liquid  fuel.  Coal  often  falls  as  low  as  8  and  liquid 
fuel  as  low  as  12. 

Reference  is  made  elsewhere  to  the  supposed  superior  effici- 
ency of  liquid  fuel  as  compared  with  solid  fuel,  in  regard  to  the 
fact  that  Nature  has  supplied  the  latent  heat  of  liquidity,  but 
it  is  also  shown  that  probably  the  effect  is  small,  the  latent 
heat  of  liquidity  being  only  a  fraction  of  that  of  vaporization. 
Gaseous  fuels,  therefore,  should  be  expected  to  give  higher 
values  than  liquid  fuels.  The  formulae  for  calculating  the 
calorific  effect  of  a  fuel  give  a  result  greater  than  the  actual 
calorimetric  values  of  hydrogen  and  carbon.  In  a  liquid  fuel 
the  carbon  should  give  more  than  its  nominal  solid  rating,  but, 
on  the  other  ha.nd,  the  rating  of  hydrogen  at  29,150  cals.  is 


CALORIFIC  AND  OTHER  UNITS  106 

obtained  from  hydrogen  gas,  and,  in  a  liquid  fuel,  the  hydrogen 
has  been  deprived  of  its  latent  heat  of  gasification,  and  by 
so  much  must  lose  effect  when  burned,  and,  per  pound,  the 
hydrogen  loses  much  more  than  is  gained  per  pound  of  carbon. 
Solid  fuels,  of  course,  lose  still  more,  but  the  difference  between 
liquid  and  solid  fuels  is  not  very  great  in  respect  of  their  differ- 
ence of  physical  condition.  Where  liquid  fuel  secures  its  high 
calorific  value  is  in  its  very  high  percentage  of  hydrogen,  and 
its  freedom  from  oxygen  and  ash.  The  absence  of  oxygen  is 
a  proof  of  the  full  efficiency  of  the  hydrogen,  except  so  far, 
of  course,  that  the  hydrogen  is  combined  with  the  carbon  and 
the  combination  when  effected  was  exothermic. 

As  a  sample  of  liquid  fuel  calculation,  a  petroleum  may  be 
taken,  such  as  a  heavy  Baku  oil,  with  87*0  per  cent,  of  carbon 
and  13  per  cent,  of  hydrogen.  The  excess  of  air  will  be  assumed 
to  be  50  per  cent,  beyond  theoretical  requirements.  The  oil 
was  tested  to  give  10,843  calories  by  Mahler. 

Calculated  by  the  improved  Dulong  formula  we  have  — 

Cal.  =  (8,100  X  0-87)  +  (29,000  x  0-13)  =  10,817  cal. 

which  corresponds  very  closely  with  the  calorimetric  test. 

Had  the  full  values  of  8,137  and  29,150  been  employed,  the 
result  would  have  been  slightly  above  the  actual  finding,  and 
for  a  very  pure  hydrocarbon  it  is  probable  that  calculation  and 
tests  will  not  prove  to  be  far  apart. 

The  temperature  secured  by  this  oil  with  the  50  per  cent. 
air  excess  will  be  — 

_  10,817  __  _ 

(•87  X  3-66  X  0-217)  +  (-13x9  X  0-479)  +  (3'36  X  3'32 

X  0-244)  +  (5-575x0-237). 

In  the  formula  the  first  term  of  the  denominator  gives  the 
heat  absorbed  by  the  C02  formed  from  0-87  of  carbon,  and  the 
oxygen  consumed  is  0-87  =  2-66  =  2-32.  The  second  term 
gives  the  heat  absorbed  by  the  steam  produced  from  0-13  of 
hydrogen,  and  the  oxygen  consumed  is  0-13  =  8  x  1*04.  The 
third  term  gives  the  heat  in  the  nitrogen  which  accompanies 
the  consumed  3'36  of  oxygen. 

The  total  weight  of  air  used  is  thus  3*36  +  (3-36  x  3-32) 
=11-15.  Then  50  per  cent,  of  this,  or  5-575,  is  put  into  the 
fourth  term  with  the  specific  heat  co-efficient  of  air.  Working 
out,  the  result  is  — 

10817 


as  the  theoretical  temperature  of  the  fuel  when  supplied  with 


106          LIQUID  FUEL  AND  ITS  APPARATUS 

50  per  cent,  excess  of  air.  This  shows  how  temperature  is 
reduced  by  excessive  air.  Granted  that  this  temperature  is 
more  than  would  actually  be  attained  owing  to  the  rise  of  the 
specific  heat  of  gases  with  the  temperature,  the  fact  remains 
that  the  furnace  temperature  would  be  more  nearly  maintained 
along  the  flues.  The  absorption  of  heat  by  the  boiler,  lowering 
the  temperature,  would  set  free  the  heat  which  has  become 
latent  under  the  term  specific  heat,  and  the  curve  of  tempera- 
ture drop  would  be  less  steep. 

But  beyond  all  this  there  is  a  final  chimney  temperature 
beyond  which  it  is  not  commercially  practicable  to  reduce  the 
gases,  and  if  by  using  too  much  air  we  double  the  weight  of 
rejected  gases,  these,  at  a  given  temperature,  will  carry  off 
just  twice  as  much  heat  as  would  be  carried  off  by  half  the 
weight.  Thus,  if  the  chimney  temperature  is  950°F.  or  400° 
above  the  atmospheric  temperature,  each  pound  of  gas  runs 
away  with  approximately  400  x  0-237  B.Th.U.=94'8  B.Th.U., 
which  is  about  1,560  B.Th.U.  per  pound  of  carbon  fuel  burned 
or  approximately  9  per  cent,  of  the  heat,  on  the  assumption 
that  the  chemical  minimum  of  air  has  been  used.  But  had  the 
air  supply  been  doubled  the  heat  thrown  away  would  have 
been  doubled  also,  and  a  loss  of  about  18  per  cent,  would  have 
been  incurred. 

Excepting  that  it  is  important  to  have  clear  ideas  upon  the 
effect  of  air  supply,  it  does  not  much  concern  the  engineer 
to  know  what  theoretical  temperatures  are  secured,  though  he 
must  be  on  his  guard  against  unduly  low  temperatures  in  the 
furnace,  and  be  prepared  to  guard  against  this  by  proper  design, 
such  as  keeping  heat-absorbing  surface  away  from  the  gases 
until  combustion  is  sufficiently  perfect  to  enable  this  to  be  done, 

The  engineer  is  usually  concerned  with  the  evaporative 
efficiency  of  a  fuel,  and  calculates  this  from  and  at  the  boiling 
point  of  100°C.  =  212°F.  The  heat  of  evaporation  of  a  kilo- 
gram of  water  is  536-5  cals.  or  965*7  B.Th.U.  per  pound.  The 
evaporative  power  of  a  fuel  is  therefore  to  be  directly  obtained 
by  dividing  its  unit  calorific  capacity  by  the  heat  of  vaporiza- 
tion of  water  from  and  at  100°C. 

For  pure  carbon  the  figure  obtained  is  — 

H  1  ^17 

E  =  2±£1  =  15-165,  or,  in  British  figures, 

'o 


the  slight  discrepancy  being  due  to  errors  in  the  equivalents 
for  want  of  unimportant  decimals. 


CALORIFIC   AND    OTHER  UNITS  107 

The  actual  evaporation  of  a  steam  boiler  neve;-  approaches 
the  calculated  figure  within  20  per  cent.  This  20  per  cent,  of 
loss  of  effect  is  due  to  several  causes  — 

(1)  The  whole  of  the  fuel  is  not  burned  perfectly. 

(2)  The  waste  gases  are  sent  away  to  the  chimney  at  a 

temperature  considerably  above  that  of  the  atmo- 
sphere at  which  the  fuel  and  air  is  supplied. 

(3)  There  is  a  large  excess  of  air  in  the  waste  gases. 

(4)  Much  heat  is  lost  by  radiation  from  the  boiler  and 

brickwork  ;  and,  with  solid  fuels,  in  ashes  and 
clinkers. 

M.  Clavenad  has  a  peculiar  method  of  calculating  calorific 
capacities.  He  points  out  that  the  figures  of  8,000  and  34,500 
for  the  solid  and  gaseous  states  of  carbon  and  hydrogen  re- 
spectively are  incorrect  for  liquid  hydrocarbons.  The  heat 
disengaged  by  gaseous  carbon  when  burned  is  equal  to  that 
disengaged  by  four  atoms  of  hydrogen  gas. 

The  atomic  weight  of  carbon  being  12,  and  one  kilogram  of 
hydrogen  having  a  power  of  34,500  calories,  then  1  kilo  of 
carbon  in  a  gaseous  hydrocarbon  will  possess  — 

calories. 


In  the  complete  combustion  of  carbon  the  first  reaction, 
C  +  0  =  CO,  produces  as  much  heat  as  the  second,  CO  +  O  — 
C02.  The  weight  of  carbon  in  one  kilo  of  CO  being  0-428  kilo, 
and  the  combustion  of  this  from  CO  to  CO2  producing  2,431 
calories,  therefore  1  kilo  of  carbon  completely  burned  must 
produce  — 

=  11,360  calories. 

Hence  M.  Clavenad  takes  the  calorific  power  of  gaseous 
hydrocarbon  as  11,500  or  11,360  for  the  carbon,  and  34,500 
for  the  hydrogen,  figures  which,  however,  will  not  fit  with 
actual  determination,  because  of  the  disturbing  effects  of 
exothermism,  as  in  the  case  of  marsh  gas,  CH4,  which  falls 
much  short  of  calculation. 

Mahler  has  shown  in  the  table  below  that  the  calculated 
calorific  capacity  on  the  assumption  of  H  =  34,511  and  C  = 
7,860  is  greater  than  experiment  shows  to  be  the  case. 

The  difference  P  —  p  is  less  for  crude  oil  than  for  products 
industrially  produced.  The  calorific  power  of  the  various  oils 
studied  ranges  from  10,300  calories  for  crude  Russian  to  11,100 
for  American  crude. 


108         LIQUID  FUEL  AND  ITS  APPARATUS 

According  to  Colomer   and  Lordier,  the  relative  weights  of 
different  fuels  to  give  equal  evaporation  are — 

Petroleum  residue 100 

Peat 320 

Coke 142 

Good  coal  briquettes 140 

Anthracite  (Donetz) 139 

Coal .      .  153 

„     Moscow  Basin 276 

„     Ural  Basin 176 

„     Kauban  Basin 140 

„     Poland 165 

„     Silesia 167 

„     English 139 

Goutal's  formula  for  calculating  the  calorific  value  of  fuel 
from  its  composition  is — 

P  =  82  C  +  aV  ;    where 

P  =  calorific  power  in  calories. 

C  —  percentage  of  fixed  carbon. 

V  =  percentage  of  volatile  matter. 

a  =  a   variable  co-efficient  depending   on   the   amount  of 
ash  and  water  in  the  fuel. 

Using  the  formula — 

_V  X  100 

•  c  +  v 

the  following  values  are  obtained  for  (a). 

V'=       5,     10,     15,     20,     25,  30,  35,  38,  40. 

a  .=  145,  130,  117,  109,  103,  98,  94,  85,  80. 
This  formula  is  applicable  to  solid  fuels. 


SMOKE  AND  COMBUSTION. 
The  Combustion  of  Hydrocarbons. 

When  hydrocarbon  fuels  are  burned  there  may  be  formed 
smoke  of  two  distinct  varieties.  The  first  is  the  greenish- 
yellow  fume  which  is  driven  off  coal  when  placed  upon  a  fire. 
This  fume  is  simply  hydrocarbon  gas  with  its  contained  tars, 
and  can  be  burned.  It  is  the  usual  smoke  produced  by  the 
domestic  fireplace,  and  burns  freely  when  an  under  fire  be- 
comes hot  and  the  gases  are  once  fairly  alight. 

The  other  variety  of  smoke  is  the  black  smoke  which  deposits 
soot.  Soot  is  a  flocculent  variety  of  carbon  which  is  produced 
by  the  sudden  cooling  of  heated  hydrocarbon  gases.  In  the 
furnace  of  a  boiler  wherein  the  green  gases  are  well  ignited 
they  are  allowed  to  come  into  contact  with  the  cold  surfaces 


CALORIFIC  AND   OTHER  UNITS 


109 


s 

3* 

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PQ 


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(M^COCO.OOOGOCO 

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o"  ^T  f-T  p-T  o  cT  o 


i—  ii—  ii—  IOOO5O 


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o 


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O5  !—  i 


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r-H  <M 


O5  XO  O 
QO  t-  (N 
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O5  Oi 

oo  "^ 
co**  10 

GO  QO 


00 


co  10 

GO  00 


r- 

10    .  co  10 

CO          O5  O5 

111         6    '    0-ln 


O5   i—  1   O5  IO 

<N  CO  O         "* 


CO  O 
i—  I   O 


oooooooooooot^oo 


vy 

n 


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ican  P 


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110          LIQUID  FUEL  AND   ITS   APPARATUS 

of  the  boiler,  and  soot  is  formed.  Had  the  green  gases  been 
supplied  with  air  intimately  mixed,  they  would  have  burned 
completely  with  no  smoke,  if  they  were  not  cooled  down  by 
the  boiler.  When  a  boiler  furnace  is  of  correct  form,  the 
combustion  of  the  hydrocarbon  gases  can  be  secured  when  a 
proper  admixture  of  air  is  carried  out,  and  in  the  Lancashire, 
Cornish,  and  other  shell  boilers,  smokeless  combustion  can  be 
approximated  if  the  draught  is  good.  The  means  of  admitting 
air  is  usually  a  grid  in  the  furnace  door.  The  air  thus  admitted 
sweeps  over  the  whole  surface  of  the  fire  and  becomes  blended 
with  the  gases  given  off  the  green  coal,  and  perfect  combustion 
will  take  place  if  there  is  sufficient  free  space  beyond  the  bridge 
in  which  flame  can  burn  unhindered  by  cold  water  pipes. 

If,  however,  the  draught  is  poor,  the  air  drawn  in  over  the 
fire  through  the  door  will  be  insufficient,  and  smoke  will  be 
produced.  About  3  to  4  square  inches  of  air  openings  are  neces- 
sary for  each  square  foot  of  grate  surface. 

When  insufficient  draught  is  due  to  the  smallness  of  the 
chimney  or  flues,  or  to  bad  brickwork,  it  can  be  remedied  by 
repairs,  or  by  the  use  of  a  small  steam  jet,  to  induce  a  flow  of 
air  through  the  door  grid. 

If  the  poor  draught  is  due  to  the  necessity  of  closing  the 
dampers  to  moderate  the  intensity  of  the  fires,  it  is  then  neces- 
sary to  reduce  the  area  of  the  fire-grate,  so  that  the  chimney 
draught  may  be  made  more  intense  on  the  smaller  area,  the 
damper  being  kept  open.  This  keeps  up  the  draught  suffi- 
ciently to  compel  the  air  to  flow  in  at  the  door  grids  in  ample 
volume.  The  same  effect  may  sometimes  be  secured  by  fitting 
dampers  to  the  ash-pit  opening,  so  as  to  control  the  intensity 
of  the  fires  even  with  a  full  open  chimney  damper.  The  full 
draught  power  then  remains  available  to  draw  in  air  through 
the  door  grids  to  burn  the  hydrocarbon  gases  above  the  fire. 
Any  draught  less  than  J-inch  water-gauge,  or  say  a  velocity  of 
30  feet  per  second,  will  usually  make  it  impossible  to  burn  coal 
without  smoke. 

In  no  case  can  smoke  be  prevented  where  the  gases  rise  verti- 
cally from  the  fire  and  pass  directly  between  the  tubes  of  a 
water-tube  boiler,  for  the  necessary  mixture  of  air  has  not  been 
secured.  Belleville  tried  to  effect  a  mixture  by  blowing  high- 
pressure  air  jets  into  the  furnace  in  order  to  mix  up  the  gases, 
but  the  method  is  faulty,  and  cannot  be  a  success  where  the 
tubes  are  so  close  above.  The  same  principles  apply  to  the 
combustion  of  liquid  fuel,  with  certain  differences  due  to  the 
method  of  firing.  With  liquid  fuel  the  supply  of  gas  is  uniform 
and  continuous,  and  the  fuel  is  supplied  in  exceedingly  small 


CALORIFIC   AND   OTHER  UNITS  111 

particles  intimately  mixed  with  air  to  begin  with,  and  supplied 
with  a  further  volume  of  air  from  below.  A  uniform  high 
temperature  is  maintained  in  the  locus  of  combustion  by  a 
sufficient  mass  of  fire-brick  work  in  the  form  of  arches  or  chequer 
work. 

The  production  of  soot  is  well  illustrated  by  the  system  of 
manufacture  of  lamp-black,  which  is  carried  on  by  burning  a 
large  number  of  oil  lamps  in  a  confined  space  with  an  insufficient 
supply  of  air  at  a  low  temperature.  Soot  is  thus  formed,  not 
alone  by  cooling  heated  hydrocarbon  gas,  but  by  attempting 
to  burn  it  with  an  insufficient  air  supply. 

Oil  fuel  will  produce  dense  smoke  when  not  supplied  with 
sufficient  air,  but  in  all  the  approved  methods  of  combustion 
the  requisite  air  is  supplied,  and  can  be  regulated  very  exactly. 
Combustion  also  takes  place  at  a  high  temperature,  and  the 
flame  produced  is  comparatively  short,  and  combustion  can  be 
completed  in  a  comparatively  restricted  space,  as  in  the  firebox 
of  a  locomotive,  which  can  be  perfectly  fired  by  oil  fuel  without 
any  change  from  the  conditions  found  necessary  with  coal.  All 
manner  of  contrivances  have  been  patented  for  the  prevention 
of  smoke,  but  few,  if  any,  have  realized  the  all-important  detail 
of  temperature,  for  without  sufficient  temperature  in  addition 
to  the  proper  mixture  of  air  in  a  furnace  of  correct  form,  there 
can  be  no  perfect  combustion. 

All  smoke  troubles  may  be  attributed  in  general  terms  to  the 
too  early  application  of  the  heat  absorbing  surfaces  of  the  boiler 
to  the  yet  unconsumed  gases.  While  the  foregoing  arguments 
apply  more  particularly  to  coal,  their  principles  are  equally 
applicable  to  oil.  Anthracite  coal,  which  contains  no  hydro- 
carbons, burns  away  altogether  at  the  grate  surface  with  an 
intensity  of  temperature  very  much  in  excess  of  that  of  any 
bituminous  coal. 

The  latter  must  be  distilled  on  the  grate,  and  much  heat  is 
absorbed  in  the  gasification  of  the  hydrocarbons.  The  zone 
of  combustion  is  very  much  extended,  the  temperature  at  the 
grate  is  less,  arid  it  is  necessary  to  conserve  the  heat  generated 
on  the  grate  in  order  to  keep  hot  the  hydrocarbon  gases,  so 
that  these  also  may  burn  and  not  be  wasted.  With  liquid  fuel 
the  gasification  is  already  partially  effected,  and  combustion 
is  rendered  more  perfect  by  heating  the  liquid  and  also  heating 
the  air  by  which  it  is  atomized.  Thus,  if  the  oil  and  air  be  both 
heated  to  200°F.,  the  temperature  of  combustion  will  be  higher 
by  about  150°F.  than  if  both  oil  and  air  were  supplied  at  the 
ordinary  atmospheric  temperature.  The  following  extract 
from  the  Author's  paper  on  the  subject  of  hydrocarbon  com- 


112          LIQUID  FUEL  AND   ITS  APPARATUS 

bustion  in  the  Electrical  Review,  of  August  30, 1901,  may  be  of  in- 
terest in  this  connexion  with  the  subject  of  furnace  temperatures. 

Furnace  Temperatures. 

An  argument  in  favour  of  the  necessity  of  refractory  furnaces 
for  bituminous  fuel  is  that  only  a  proportion  of  the  total  calorific 
capacity  of  a  bituminous  coal  is  generated  on  the  grate,  and 
therefore  the  fuel  which  burns  on  the  grate  is  debited,  not  only 
with  its  own  combustion,  but  also  with  the  splitting  up  of  the 
hydrocarbons  and  other  volatiles,  and  raising  them  to  such 
temperatures  as  will  enable  them  to  burn  at  a  second  zone  of 
combustion. 

An  average  of  18  analyses  of  Newcastle  coal  gives  the  follow- 
ing figures- 
Fixed  carbon 48-84  per  cent. 

Volatile  carbon 33-29 

Hydrogen 5-31 

Oxygen  . 5-69 

Nitrogen 1-35 

Sulphur 11-24 

Ash 3-77 

Calorific  capacity 15,203  B.Th.U. 

The  calorific  capacity  of  amorphous  carbon  is  about  14,647 
B.Th.U.  per  pound  ;  therefore  the  capacity  of  the  48-84  per 
cent,  of  fixed  carbon  in  the  above  samples  must  be  7,150  B.Th.U. 
As  regards  the  fire  upon  the  grate,  these  7,150  heat-units  are 
all  we  have  to  work  with.  We  have  to  draw  on  them  for  the 
heat  which  becomes  latent  in  converting  the  solid  coal  to  the 
gaseous  hydrocarbon.  A  piece  of  coal  is  all  solid,  and  except- 
ing the  ash,  it  all  becomes  gaseous.  Subtracting  for  cinders 
3-77  per  cent.,  there  remains  47-0  per  cent,  of  volatile  solid 
matter,  which  ultimately  passes  off  in  a  gaseous  state.  The 
customary  allowance  of  air  is  about  18  pounds  per  pound  of 
coal.  This  also  must  be  heated  up  to  the  general  temperature 
by  the  heat  developed  on  the  grate  by  the  fixed  carbon  only. 

The  theoretical  flame  temperature  of  carbon  when  burned  in 
an  exact  sufficiency  of  air  (i.e.  11 J  pounds  per  pound)  is  4,892°F. 
We  can  readily  calculate  the  net  temperature  of  all  the  products 
in  the  usual  manner,  though  the  result  will  be  approximate 
only.  We  may  assume  1  pound  of  coal,  and  we  will  add  the 
customary  18  pounds  of  air,  so  as  to  produce  a  final  19  pounds 
of  the  total  furnace  products.  As  the  temperature  of  combus- 
tion of  carbon  in  air  is  4,892°F.,  when  using  11-6  times  its 
weight  in  air,  the  temperature  with  18  pounds  of  air  will  be 

12  6 
--  x  4,892  =  3,245°I\     But   with   the   heat   produced   by 


CALORIFIC  AND   OTHER  UNITS  113 

48-84  per  cent,  of  the  coal,  we  have  to  carry  the  further  load  of 
volatile  fuel  and  inert  ash  that  is  not  burned  on  the  grate, 
together  with  its  similar  proportion  of  excess  air.  The 
temperature  of  3,245°F.  x  -4884  =  1,584°F.,  and  this  is  the 
maximum  temperature  of  the  products  of  combustion,  assum- 
ing that  they  escape  uncooled.  This  is  a  maximum  figure, 
because  whereas  the  temperature  of  combustion  in  air,  namely 
4,892°,  is  that  due  to  a  minimum  of  air,  the  reduced  tempera- 
ture involved  by  the  use  of  excess  of  air  as  above  calculated  is 
really  too  great  in  part  proportion  as  the  specific  heat  of  nitro- 
gen is  greater  than  that  of  carbonic  acid  ;  nitrogen,  of  course, 
forms  by  far  the  greater  proportion  of  the  furnace  products, 
and  it  has  a  specific  heat  of  0-244,  as  compared  with  carbonic 
acid  0-217.  Steam  also,  which  is  formed  on  the  grate  and 
does  its  share  in  reducing  the  temperature,  has  the  high  specific 
heat  of  0-480,  any  free  hydrogen  that  may  escape  has  3-410, 
and  the  hydrocarbons  have  also  very  high  specific  heats,  for 
example,  olefiant  gas,  0-418  ;  marsh  gas,  0-593. 

It  is  thus  clear  that  the  temperature  of  the  gases  as  they 
flow  to  the  bridge  is  quite  low,  and  so  far  no  deduction  has 
been  suggested  for  the  vaporization  of  fully  half  the  solid  fuel 
into  gaseous  form.  What,  in  fact,  is  the  effect  of  the  latent  heat 
of  evaporating  carbon,  hydrogen,  oxygen,  from  the  solid  ?  for 
this  is  really  what  happens  when  bituminous  coal  is  burned. 

To  evaporate  carbon  requires  5,817  British  Thermal  Units 
per  pound,  this  being  the  difference  between  the  calorific  capa- 
city of  carbon  burned  to  its  monoxide,  and  of  this  monoxide 
burned  to  dioxide  respectively.  Hydrogen  and  oxygen  com- 
bined require  11,000  heat-units  per  pound  of  hydrogen  to  raise 
them  from  the  solid  to  the  gaseous  state. 

Let  the  figure  of  7J0001  units  of  latent  heat  per  pound  be 
assumed  for  the  whole  of  the  volatile  constituents  of  coal,  that 

1  Possibly  the  figure  of  7,000  may  be  too  high,  except  for  the  carbon 
and  hydrogen  compounds.  The  value  of  carbon  is  as  above  about 
6,000,  as  evidenced  by  the  difference  between  the  heat  produced  by 
burning  carbon  to  its  first  oxide,  and  then  again  to  its  second  oxide. 
That  for  hydrogen  must  be  over  7,300,  but  the  values  for  oxygen 
and  nitrogen  are  low.  Lechatelier  determined  the  molecular  specific 
heats  of  the  elements  as  6-65  +at,  where  a  is  the  constant,  and  t  is  the 
absolute  temperature  at  which  the  measurement  is  taken,  a  was  given 
by  him  as  0-001  for  a  considerable  number,  but  he  gave  values  for 
a  =  0-008,  and  there  is  ample  proof  in  Berthelot's  great  work  that  at 
high  temperatures  the  specific  heats  of  some  substances  may  be  double 
and  treble  the  customary  figure  of  6-65.  As  the  distillation  of  coal 
in  a  furnace  is  desired  to  be  effected  at  at  least  1,000°  or  1,500°F.  (say 
550°C.  to  800°C.)  the  specific  heats  will  be  something  higher  than  6 -65. 

5 


114          LIQUID  FUEL  AND   ITS   APPARATUS 

is  to  say,  for  all  that  part  which  does  not  burn  directly  on  the 
grate.  This  proportion  was  found  above  to  be  47  0  per  cent, 
of  the  whole,  so  that,  per  pound  of  fuel,  3,290  heat-units  (-470 
X  7,000)  must  disappear  in  evaporating  the  volatile  carbon, 
the  oxygen,  hydrogen,  and  other  gases  which  exist  in  combined 
solid  form  in  coal. 

But  we  have  already  found  that  the  total  heat  generated  by 
the  48-84  per  cent,  of  fixed  carbon  produces  7,150  heat-units. 
The  difference  between  the  heat  generated  by  the  fixed  carbon 
and  that  absorbed  by  the  volatile  hydrocarbons  of  these  parti- 
cular Newcastle  coals  is  thus  only  3,870  units.  This  is  all  the 
heat  that  remains  available  for  raising  the  temperature. 

Now  we  have  found  an  ultimate  temperature  of  1,584  when 
not  allowing  for  the  latent  heat  of  gasification.  We  must 
correct  this.  It  is  less  in  the  ratio  of  3,870  :  7,150,  or  857°F. 
That  is  to  say,  if  bituminous  coal  be  burned  on  a  grate  and 
those  parts  of  the  coal  which  volatilize  and  burn  as  flame  be 
gathered  unburned,  the  temperature  of  the  whole  production 
of  the  furnace,  including  18  pounds  of  air  per  pound  of  fuel, 
would  only  be  857°,  or  considerably  less  than  that  necessary  for 
ignition. 

In  the  first  place,  this  tells  us  that  it  is  of  the  first  importance 
to  diminish  the  supply  of  air  to  a  minimum. 

By  passing  only  half  the  air  through  the  grate  and  adding 
the  remainder  as  required  to  the  evolved  gases  at  a  subsequent 
point,  we  can  at  once  practically  secure  double  the  above  tem- 
perature, or  say  1,600°,  a  temperature  at  which  ignition  is 
possible.  Moreover,  even  9  pounds  of  air  is  35  per  cent,  in 
excess  of  the  allowance  necessary  to  burn  the  fixed  carbon  of  a 
pound  of  bituminous  coal,  so  that  it  would  be  liberal  practice 
to  pass  only  half  the  total  air  through  the  grate.  Some  of  the 
heat  developed  on  the  grate  is  at  once  radiated  to  the  boiler 
surfaces  ;  hence  my  constant  contention  that  furnaces  should 
be  lined  wholly  or  partially  with  refractory  material  in  order 
to  conserve  the  necessary  temperature. 

It  must  not,  again,  be  overlooked  that  some  of  the  evolved 
hydrocarbons  do  burn  on  the  grate  and  at  the  fire  surface.  In 
fact,  they  commence  to  burn  at  once,  and  continue  to  burn  to 
the  end  so  long  as  conditions  are  maintained  favourable  to 
continuous  combustion. 

Rankine's  estimate  of  air  as  found  in  ordinary  practice  was 
25  pounds  per  pound  of  fuel.  The  so-called  chemical  minimum 
is  11|  pounds.  I  have  assumed  18  pounds  as  good  practice, 
but  as  low  or  lower  than  15  pounds  has  already  been  recorded 
by  Mr.  Michael  Longridge. 


CALORIFIC  AND   OTHER  UNITS  115 

If,  however,  we  pass  9  pounds  of  air  through  the  grate  and, 
say,  a  further  6  pounds  over  the  grate,  in  fine  streams,  to  assist 
the  combustion  of  the  hydrocarbons,  and  take  care  that  we 
do  not  abstract  heat  faster  than  it  is  generated  by  the  burning 
gases,  we  ought  to  be  able  to  secure  perfect  combustion  with 
less  than  18  pounds  of  air  per  pound  of  coal.  There  is  no 
known  reason  why  we  should  not.  The  impossibility  of  smoke- 
less combustion  has  been  widely  and  influentially  urged,  but 
never  so  much  as  by  those  engineers  who  cram  their  heating 
surfaces  right  upon  the  fire  and  never  trouble  their  brains  to 
inquire  why  it  is  that  a  thermometer  shows  the  same  continu- 
ous reading  of  32°F.  in  a  vessel  of  melting  ice  with  a  flame 
under  it  until  all  the  ice  is  melted.  A  piece  of  coal,  like  a 
piece  of  ice,  is  simply  so  much  solidified  gas,  and  absorbs 
heat  greedily  while  vaporizing,  but  it  cannot  be  burned  like  so 
much  solid  carbon,  but  must  have  length  and  space  in  which 
to  mix  and  combine  with  the  oxygen  of  the  air. 

The  following  figures,  based  on  Berthelot's  investigations, 
will  be  useful  in  this  connexion,  for  they  show  the  enormous 
differences  which  exist  between  matter  in  its  several  states. 
Carbon,  existing  as  it  does  free  in  Nature  in  at  least  three  solid 
allo tropic  modifications,  is  a  peculiarly  interesting  example. 
We  do  not  know  it  as  a  liquid  or  as  a  gas  except  in  combi- 
nation. Its  three  solid  forms  of  crystalline,  graphitic,  and  amor- 
phous, show  by  their  variations  of  "  latent  "  heat  how  great 
is  the  effect  of  form,  even  when  the  various  forms  affect  one 
state  alone.  The  gaseous  state  of  carbon  and  the  heat  neces- 
sary to  put  it  into  that  state  are  easily  argued  from  the  difference 
of  heat  disengagement  in  the  two  oxidations.  As  the  table 
shows,  the  oxidation  of  1  pound  of  carbon  (diamond)  produces 
3,915  British  thermal  units  when  the  product  is  monoxide. 
The  heat  disengaged  by  complete  oxidation  is  14,146  units. 
The  difference  of  10,231  -  3,915  =6,316  units,  and  this  is 
obviously  the  minimum  heat  of  vaporization  of  the  diamond. 
Similarly,  for  the  amorphous  forms  of  carbon,  the  first  oxida- 
tion produces  4,415  units,  and  the  complete  oxidation  produces 
14,647.  Here  the  same  difference  is  5,817,  and  the  greater 
heat  evolution  represents  the  energy  necessary  to  recrystallize 
the  diamond.  Thus  we  learn  that  when  the  diamond  crystal- 
lized it  evolved  heat,  and  we  learn  that  the  difference  between 
graphite  and  the  diamond  is  less  than  between  graphite  and 
amorphous  carbon.  In  fact  graphite  is  about  six-sevenths 
along  the  road  to  becoming  diamond. 


116          LIQUID  FUEL  AND  ITS  APPARATUS 

Heat  generated  by  the  Combustion  of  1  pound  of  Carbon. 


State  of  Carbon. 

Product  of  Combustion. 

British  Thermal  Units 
per  pound. 

Diamond  

Cai 
i 

"bon  monoxide 
,        dioxide 
»i 
monoxide 
dioxide 
monoxide 
dioxide 
»> 

3,915 
14,146 
14,222 
4,415 
14,647 
10,232 
20,463 
10,231 

Graphite  
Amorphous   .... 
»            .... 
Gaseous   

2£  carbon  monoxide     . 

Metamorphic  Conversions. 

Heat  absorbed. 

Car 

bon  (diamond)   . 
(graphite)    . 

Gas  

6,316 
6,241 
5,817 
499 

74-7 
424 

(amorphous) 
(diamond)    . 
(diamond)    . 
(graphite)    . 

Carbon  (amorphous)   . 
„        (graphite)  . 
,,        (amorphous)    . 

Stated  briefly,  about  half  the  weight  of  a  bituminous  fuel 
burns  upon  the  grate  itself,  and  produces  half  the  total  heat  of 
combustion  ;  but  that  owing  to  the  heat  of  formation  of 
gaseous  hydrocarbons,  and  generally  to  the  vaporization  of 
solid  fuel,  which  absorbs  so  much  heat,  only  about  one-fourth 
of  the  total  heat  of  combustion  is  sent  off  from  the  grate  as 
sensible  heat.  The  remaining  three-fourths  are  developed 
between  the  fire  surface  and  the  extreme  range  of  combustion. 
This  range  varies,  of  course,  with  the  short  or  long  flaming 
quality  of  the  coal.  Anthracite  coal,  which  is  entirely  of  solid 
carbon,  and  is  therefore  almost  wholly  burned  upon  the  grate, 
will  produce  a  temperature  at  the  surface  of  the  grate  very 
considerably  higher  than  bituminous  coal  will  produce  con- 
tinuously. This  is  the  reason  why  so  much  trouble  is  experienced 
with  the  grate  bars  when  anthracite  is  used.  It  is  evident  that 
every  fresh  charge  of  bituminous  coal  has  a  very  chilling  effect 
upon  the  fire,  and  this  is  especially  the  case  with  intermittent 
firing.  .  The  chilling  effect  of  a  fresh  charge  of  anthracite  is 
merely  that  due  to  the  heating  of  solid  fuel,  and  is  compara- 
tively trivial.  The  bad  effect  of  anthracite  coal  upon  grate 
bars  is  usually  attributed  to  some  specially  bad  quality  in  the 
coal  itself  ;  but  this  is  probably  erroneous,  the  real  cause  being 
simply  the  high  temperature,  which  melts  the  cast-iron  bar. 
This  explanation  receives  confirmation  in  the  fact  that  bars  go 
very  quickly  when  they  stand  above  the  general  surface  of  the 


CALORIFIC  AND  OTHER  UNITS  117 

grate,  projecting  their  upper  edge  into  the  body  of  the  fire. 

The  question  of  combustion  is  further  complicated  by  the 
variation  of  the  specific  heat  of  gases  at  high  temperatures. 

The  subject  has  been  most  thoroughly  investigated  by  M. 
Berthelot,  to  whose  great  work,  Thermochimie,  it  is  hardly 
necessary  to  say  the  Author  is  much  indebted.  That  the  specific 
heat  of  gases  does  increase  with  temperature  there  is  now  no 
doubt.  At  ordinary  furnace  temperatures  the  effect  is  not 
great,  but  such  as  it  is,  is  in  the  direction  of  keeping  down 
temperatures  below  what  they  would  appear  to  be  when  calcu- 
lated on  the  basis  of  constant  specific  heat  at  all  temperatures. 

First,  only  half  the  coal  is  burned  actually  on  the  grate  ; 
secondly,  the  other  half  and-  the  excess  of  air  work  ever  to 
reduce  the  temperature  ;  thirdly,  there  is  the  reducing  effect  of 
vaporizing  half  the  fuel,  and  this  is  simply  enormous,  and  has 
never  before  been  recognized  as  considerable,  if  indeed  it  has 
even  been  allowed  to  suggest  itself  ;  fourthly,  there  are  the 
very  active  heat-absorbing  surroundings  of  water-cooled  plates 
or  pipes.  All  these  causes  work  together,  with  the  further 
assistance  of  the  increment  of  specific  heat,  to  reduce  the  pro- 
ducts of  bituminous  coal  to  a  temperature  below  that  at  which 
perfect  combustion  is  possible.  The  combined  action  is  so 
powerful  that  even  so-called  smokeless  Welsh  coal  will  smoke 
in  boilers  of  the  Belleville  type. 

In  any  case,  even  if  the  effect  of  vaporizing  the  solid  fuel 
has  been  over-estimated,  the  fact  remains  that  it  nearly  ap- 
proaches the  figures  given,  and  must  prejudicially  affect  the 
furnace  temperature.  It  teaches  us  at  once  the  complication 
involved  in  burning  bituminous  coal,  and  the  hopelessness  of 
those  forms  of  furnace  that  attempt  to  extract  heat  from  the 
fire  within  a  short  distance  of  the  fire  itself,  and  this  is  equally 
applicable  to  liquid  fuels  which  indeed  are  so  very  offensive 
if  badly  burned  that  they  usually  are  furnished  with  brick 
linings  for  heat  conservation  and  are  burned  without  smoke. 


Flame  Length. 

The  length  of  flame  from  a  burning  hydrocarbon  is  largely 
determined  by  the  intensity  of  the  combustion,  as  well  as  by 
the  perfection  of  the  air  admixture.  A  well  mixed  gas  burning 
at  a  high  temperature  will  produce  a  short  flame,  whereas  the 
same  gas  burned  in  water-cooled  boiler  flues  will  produce  exceed- 
ingly long  flames.  By  using  suitable  furnaces  with  refractory 
linings,  combustion  may  be  made  to  complete  itself  in  a  short 


LIQUID  FUEL  AND  ITS  APPARATUS 

distance.  It  does  not  follow  because  a  certain  fuel  produces  a 
flame  60  or  80  feet  in  length  that  it  will  be  necessary  to  line 
the  combustion  space  to  a  distance  of  60  or  80  feet. 

The  very  fact  of  lining  it  for  one-tenth  that  length  might  so 
promote  rapid  combustion  as  to  shorten  the  flame  to  even  less 
than  one-tenth.  Once,  however,  that  the  initial  temperature 
is  reduced  below  a  certain  figure,  the  length  of  flame  cannot  be 
kept  within  bounds.  This  is  important  to  remember,  for  even  a 
hot  flame  will  be  extinguished  after  it  has  encountered  the  cold 
tubes  of  a  water  tube  boiler.  In  comparing  water  tube  and 
cylinder  boilers,  it  should  be  noted  that  the  area  of  cold  surfaces 
over  the  fire  of  a  cylinder  boiler,  either  internally  or  externally 
fired,  is  a  very  small  proportion  of  the  whole  heating  surface. 
In  the  ordinary  form  of  water  tube  boiler,  where  the  gases  rise 
directly  between  the  water  tubes,  the  proportion  of  cold  surface 
at  once  encountered  by  them  is  very  great.  Apart  from  the 
errors  already  pointed  out,  the  vertical  rise  of  the  gases  from 
the  fire  is  bad  practice. 

The  water  tube  boiler  need  not  of  necessity  be  thus  badly 
arranged.  It  can  be  set  to  give  the  most  perfect  combustion. 
Perfect  combustion  only  takes  place  at  a  high  temperature. 

Flame  Analysis. 

The  vibration  velocity  of  light,  by  which  is  meant  those 
etheric  waves  which  are  capable  of  making  their  existence  felt 
to  our  organs  of  vision,  varies  from  four  hundred  billion  oscil- 
lations per  second  to  nearly  eight  hundred  billions  ;  that  is  to 
say,  about  one  octave  alone  comes  within  the  capacity  of  the 
eye  to  discern.  The  lower  number  corresponds  with  the  extreme 
red  of  the  spectrum,  the  higher  frequency  with  the  extreme 
violet.  Beyond  the  extreme  red  is  a  long  range  of  oscillations 
- — rays  invisible  to  the  eye — which  manifest  themselves  as 
heat.  Beyond  the  extreme  violet  rays  exist  a  long  series  of 
invisible  rays  known  as  actinic  or  chemical  rays.  These  are  the 
rays  which  are  most  energetic  in  producing  chemical  effects. 
They  are  the  active  rays  in  photography,  and  are  those  which 
produce  sunburn  and  the  like  effect  from  exposure  to  electric 
light.  As  these  ultra-violet  rays  produce  chemical  effects,  so 
are  they  produced  by  chemical  action.  The  more  intense  the 
act  of  chemical  combination,  as  in  the  burning  of  carbon,  the 
greater  will  be  the  actinism  of  the  light  produced.  Very  high 
temperatures  produced  by  combustion  approach  a  white 
colour  the  more  closely  as  the  temperature  rises,  and  to  some 
eyes — fatigued  by  too  much  observation  of  molten  cast-iron — 


CALORIFIC  AND   OTHER  UNITS  119 

the  clearance  of  the  final  hot  slag  gives  a  peculiar  neutral  light 
lavender  colour  indicative  of  the  high  temperature  of  a  common 
foundry  cupola. 

The  proportion  of  rays  of  any  particular  colour  in  a  furnace 
will  indicate  the  intensity  of  the  action  which  is  going  on  with- 
in that  furnace.  It  is  extremely  difficult  for  the  most  highly 
experienced  eye  to  discern  the  full  action  of  a  furnace  at  high 
temperature — not  perhaps  so  much  because  of  inability  to 
estimate  the  relative  amounts  of  colour  present  as  because  of 
the  superabundance  of  heat  rays  which  accompany  the  chemical 
rays,  and  generally  the  dazzling  effect  of  even  moderate  tem- 
peratures. 

The  extreme  brightness  of  the  steel  furnace  has  necessitated 
the  use  of  blue  or  violet  coloured  glass  to  enable  the  workmeij 
to  watch  the  progress  of  the  melt  without  discomfort. 

Engineers  have  not  accepted  as  they  ought  to  accept  the 
teachings  of  physics  as  an  aid  to  correct  practice.  Science  and 
practice  have  been  kept  apart.  In  the  combustion  of  fuels, 
this  neglect  of  scientific  teaching  is  almost  universal.  The 
combustion  of  fuel,  especially  of  bituminous  coal,  is  carried 
out  along  extremely  unscientific  lines.  The  assertion  is  some- 
times made  that  the  hydrogen  of  bituminous  coals  cannot 
be  counted  upon  as  useful  calorifically.  This  conclusion  is 
erroneous. 

Hydrogen  ignites  so  very  much  more  readily  than  carbon,  and 
at  so  low  a  temperature,  that  the  probability  is  the  hydrogens 
do  burn,  and  in  doing  so  they  snatch  the  available  oxygen 
from  the  surrounding  air  and  deprive  the  nascent  carbon  of 
any  opportunity  of  combustion,  causing  it  to  deposit  as  soot. 
Unless  there  is  sufficient  temperature  there  is  no  hope  of  burn- 
ing bituminous  coal  or  oil,  as  it  very  easily  can  be  burned, 
without  the  formation  of  smoke.  Temperature  is  so  closely 
connected  with  actinism  that  the  analytical  investigation  of 
the  light  of  a  furnace  will  give  a  fair  insight  into  its  conditions 
of  temperature.  By  means  of  transparent  media  of  suitable 
composition  light  may  be  analysed  in  a  manner  that  will  afford 
great  assistance  in  arriving  at  sound  engineering  conclusions 
and  practice.  Such  media  are  coloured  glasses.  A  ruby- 
coloured  glass  will  cut  off  all  rays  of  light  of  higher  vibration 
than^ruby  colour.  Only  the  lower  end  of  the  spectrum  will 
be  visible  through  such  a  glass.  On  the  other  hand,  by  means 
of  a  violet-coloured  glass,  all  the  less  active  rays  than  violet 
will  be  eliminated,  and  the  most  brilliant  of  furnaces  may  be 
thereby  rendered  easily  visible,  its  interior  being  coloured  the 
peculiar  lavender  grey  colour,  or  approaching  this  tint,  which 


120         LIQUID  FUEL  AND  ITS  APPARATUS 

marks  the  ultra-violet  end  of  the  spectrum.  The  more  perfect 
the  combustion,  the  larger  will  be  the  proportion  of  violet 
light  emitted  by  the  flames. 

In  a  well-designed  furnace,  the  whole  internal  surface  of 
which  is  brilliantly  incandescent,  light  proceeds  from  every 
portion  of  the  area  and  from  the  flame  itself.  There  are  no 
non-luminous  areas.  Occasionally  in  the  mass  of  flame  dark 
streaks  may  be  seen.  These  represent  streams  of  burning 
gas,  which,  while  incandescent,  are  below  the  violet  stage. 
They  may  be  traced  to  a  point  of  disappearance,  and  they 
would  probably  radiate  some  light  if  the  colour  of  the  glass 
were  less  violet  and  more  blue. 

Let  the  observation  now  be  transferred  to  a  less  perfect 
furnace,  such  as  that  of  the  common  setting  of  the  water  tube 
boiler,  where  the  flames  rise  vertically  among  the  tubes  from 
the  grate  surface,  and  good  combustion  is  impossible.  With 
the  unprotected  eye  the  flames  will  appear  to  be  giving  light 
all  the  way  from  the  fire  surface  to  between  the  tubes.  Com- 
bustion appears  fair.  If,  however,  these  light-giving  flames 
be  examined  by  the  aid  of  violet  glass,  they  will  be  cut  down  to 
short  tongues  of  flame  projecting  but  little  above  the  fire  sur- 
face. Even  these  tongues  of  flame  give  forth  little  illumination. 
Above  the  flames  the  gases  appear  to  be  simply  dark-coloured 
streams  of  gas,  soot  laden  and  murky.  The  violet  glass  or 
analyser  has  cut  out  all  the  rays  of  small  actinic  power  and 
small  temperature,  with  the  result  that  the  only  remaining 
light  rays  are  those  immediately  above  the  furnace. 

The  effect  of  radiation  is  to  cool  the  flames  below  the  range 
of  violet  long  before  they  have  risen  to  the  level  of  the  tubes. 
Apparently  there  is  nothing  but  radiation  to  explain  the  reduc- 
tion of  temperature. 

This  method  of  analysis  of  the  products  of  the  fire  is  useful 
not  merely  because  it  enables  a  furnace  interior  to  be  visually 
examined  with  ease  and  comfort,  but  because  it  shows  so 
clearly  the  effect  of  a  good  design  and  the  bad  influence  of 
premature  cooling.  It  affords  most  conclusive  testimony  to 
the  benefits  that  accrue  from  proper  design,  and  should  be  an 
effectual  silencer  of  those  who  argue  that  smoke  is  one  of  the 
unfortunate  inevitables  of  combustion  in  place  of  being  but  a 
proof  of  ignorant  and  careless  design  and  neglect  of  the  plainer 
principles  of  chemical  science. 

The  use  of  violet-coloured  glass  is  essential.  It  is  not 
simply  that  it  is  requisite  to  reduce  the  amount  of  light  which 
meets  the  eye  and  renders  vision  impossible.  Such  a  result 
could  be  attained  by  means  of  glass  otherwise  coloured,  as  by 


CALORIFIC  AND   OTHER  UNITS 


121 


smoke,  so  that  it  is  less  transparent,  but  still  not  diffusive,  as 
is  ground  glass. 

Violet  glass  or  the  higher  blue  colours  are  necessary  because 


Fig.  7, 


WEIR  SMALL  TUBE  BOILER,  WITH  REFRACTORY  COMBUSTION 
CHAMBER. 


The  walls  of  the  furnace  are  lined  with  fire-brick  slabs,  threaded  on  the  inside  row  of  tubes, 
and  beyond  the  furnace  chamber  is  a  further  combustion  chamber  also  lined  with  fire-brick.  The 
hydrocarbon  gases  have  thus  a  long  distance  to  travel  before  they  reach  any  serious  area  of  cool 
tube  surface ;  the  furnace  is  maintained  at  a  high  temperature,  and  there  is  large  space  for  the 
combustion  of  the  gases  in  a  hot  chamber,  whereby  alone  combustion  can  be  secured  perfect.  This 
boiler  can  be  fixed  either  from  side  or  ends,  and  represents  the  latest  and  most  improved  practice 
in  water  tube  boilers,  recognizing  the  principles  essential  to  perfect  combustion.  The  hot  gases 
travel  along  the  length  of  the  tubes,  completely  enveloping  them.  The  outer  casing  is  of  fire-brick 
slab  with  an  outer  sheet  of  steel.  The  following  shows  result  of  tests  of  two  of  these  boilers 
with  coal — 


Grate  surface 


Ratio  to  heating  surface 

Funnel  draught 

Calorific  value  of  coal- 

Coal  per  square  foot  per  hour  .... 
Evaporation  per  Ib.  of  coal  from  and  at  212' 
Ditto  per  square  foot  heating  surface 

Boiler  efficiency , 

Fire  thickness , 

Funnel  temperature 

Steam  pressure,  Ib 285 


Single  -ended. 

Double-ended. 

48-75             48-75 

53                        53 

1                       1 

1                         1 

45                   45 

4T3                 4l¥ 

3-21  forced   0-6  nat. 

3-5  forced     0-625  nat. 

13-38             13-38 

13-2               13-2 

62-2               29 

63-4               29-1 

9-05  Ib.        10-7  Ib. 

8-65  It.          9-76  Ib. 

12-5  Ib.           6-918  Ib. 

13-27  Ib.         6-86  Ib. 

67-65              80-0 

65-5               74 

12  in.            12  in. 

9  in.              9  in. 

—                 789°F. 

930°F.           780  °F. 

185                 251 

275                276 

of  their  specially  analytical  properties.  I  am  not  prepared  to 
say  that  perfect  combustion  cannot  occur  at  temperatures 
below  those  which  are  associated  with  the  light  rays  that  can 
traverse  violet  glass.  It  is,  however,  very  probably  true  that 


122          LIQUID  FUEL  AND  ITS  APPARATUS 

the  violet  degree  of  actinism  must  be  very  fully  developed  if 
combustion  is  to  be  perfect,  and  this  degree  of  actinic  effect 
cannot  be  associated  with  temperatures  that  can  be  secured 
in  any  furnace  so  arranged  that  the  gases  rise  vertically  from 
the  grate  surface  to  pass  between  the  water  pipes  before  they 
have  been  thoroughly  commingled  and  burned  in  a  free  space. 


Jghl  Gray  : 
No  3. 


Darker  Gray  Smoke 


_Vcry  Dark  Cray  Snjoke, 


Fig.  8.     RINGELMANN'S  SMOKE  CHAET.     No.  0 — ALL  WHITE.     No.  5— 

ALL  BLACK. 

Thus  the  ordinary  arrangement  of  water-tube  boilers  is  abso- 
lutely hopeless  and  impossible.  A  single  inspection  of  such  a 
furnace  through  the  analyser  will  effectually  convert  any  open 
mind,  and  point  the  necessity  for  better  practice. 

Mr.  Weir,  of  Glasgow,  designed  the  small  tube  boiler  shown 
in  the  Fig.  7,  with  the  necessities  for  combustion  before  him. 


CALORIFIC  AND   OTHER  UNITS  123 

It  will  be  observed  that  in  this  boiler  the  gases  from  the  coal 
must  pass  through  a  large  firebrick-lined  furnace  and  com- 
bustion chamber  before  they  reach  the  tubes.  Combustion 
is  thus  assured  by  a  sufficient  conservation  of  temperature. 
The  principles  which  underlie  perfect  combustion  are  here 
assured,  and  smokelessness  results.  The  same  principles 
applied  to  liquid  fuel  are  followed  by  equally  happy  results. 

But  in  recent  practice  with  liquid  fuel  it  is  found  possible 
to  attain  very  good  combustion  with  little  or  no  smoke  without 
fire-brick  lining  to  the  furnace.  See  the  latest  practice  of  the 
Wallsend  Slipway  and  Engineering  Co. 

Ringelmann's  Smoke  Chart. 

This  chart  (fig.  8)  is  very  useful  as  a  means  of  comparing 
smoke.  The  chart  should  be  ruled  in  squares  of  about  eight 
inches,  and  hung  about  50  feet  from  the  observer,  at  which 
distance  each  square  assumes  a  uniform  tint  all  over,  the  rulings 
being  indistinguishable.  There  are  six  cards  in  a  set  No.  0 
being  all  white  and  No.  5  all  black. 
The  proportion  of  the  lines  is  as  follows — 

No.  1.  Black  lines  1  mm.  thick,  spaces       9  mm.  wide 

No.  2.  „        „  2-3  mm.       „           ,,  7-7     „       „ 

No.  3.  „        „  3-7                „           „  6-3     „       „ 

No.  4.  ,  5-5  4-5 


J5  *  **         J)  5) 


The  illustrations  are  reduced  from  a  larger  size,  and  the  pro- 
portion of  black  and  white  is  of  course  preserved. 

In  marine  work  smoke  may  be  observed  by  means  of  windows 
placed  in  the  uptakes.  An  incandescent  lamp  on  the  other 
side  of  the  uptake  should  be  visible  through  the  smoke.  It 
should  not  be  perfectly  clear,  for  an  entire  absence  of  smoke 
may  indicate  an  excess  of  air.  A  slight  smoke  indicates,  when 
conditions  generally  are  good,  that-  air  is  not  greatly  in  excess. 


Part  II 
PRACTICE 


CHAPTER    VII 

OIL      FUEL      AT      SEA. 

Oil  Storage  on  Ships. 

OBVIOUSLY  the  double  bottom  of  a  ship  now  used  for 
water  ballast  is  the  place  in  which  to  carry  oil  fuel,  leaving 
other  spaces  free. 

As  each  fuel  tank  is  emptied  it  can  be  filled  with  water. 
Lloyds'  Register  of  Shipping  publishes  certain  rules  applicable 
to  existing  vessels,  which  should  be  studied.  As  they  may 
be  changed  from  time  to  time,  they  are  not  given  in  this  book. 
Both  Lloyds  and  the  Board  of  Trade  place  only  necessary 
safeguards,  and  do  not  oppose  the  use  of  liquid  fuel.  Sir 
Fortescue  Flannery  states  that  the  peculiarly  penetrative 
qualities  of  refined  petroleum  do  not  attach  to  the  more  viscous 
fuel  oil,  which  he  avers  to  be  as  easy  to  retain  as  water  by  the 
same  class  and  quality  of  riveted  work. 

Additional  water-tight  subdivision  is,  however,  advised  as 
a  safeguard  against  the  scend  of  a  half -empty  oil  tank,  but  in 
small  or  medium  ships  the  usual  subdivision  is  thought  sufficient. 

In  the  system  of  storage  adopted  on  the  s.s.  Murex,  a  vessel 
with  all  her  tanks  adapted  to  carry  either  general  cargo  or 
refined  oil,  but  not  originally  planned  for  using  liquid  fuel,  for 
which  purpose  she  was  converted  by  the  Wallsend  Slipway 
and  Engineering  Company,  there  is  no  double  bottom  below  the 
cargo  tanks,  which  extend  to  the  skin  of  the  ship,  but  the  bottom 
is  double  below  the  engines  and  boilers,  and  coffer-dams  are 
put  in  at  the  fore  and  aft  ends  of  the  cargo  space,  and,  with  the 
fore  and  aft  peaks,  have  been  arranged  to  take  the  fuel  oil. 
Service  tanks  were  placed  in  the  'tween  decks. 

A  flange  on  deck  is  coupled  up  to  the  pipe  from  the  store 
tank,  and  oil  passes  by  pipes  to  the  various  tanks,  wrhence  a 
pump  lifts  it  to  the  service  tanks,  which  are  provided  with 
overflow  pipes,  steam  heater  coils,  and  water  drain  pipes. 

All  leakage  in  the  power  compartment  is  intercepted  by  the 
drainage  wells,  so  that  the  ordinary  bilge  is  kept  free.  These 
intercepting  wells  have  their  own  suction  and  delivery  pipes. 

127 


128         LIQUID  FUEL  AND   ITS  APPAKATUS 

In  a  regular  oil  tank  steamer  on  the  Flannery-Boyd  system, 
the  oil  to  be  used  is  carried  in  the  fore  and  aft  peaks  and  in 
the  ballast  tanks  under  the  engines  and  in  the  division  bulk- 
heads, the  cargo  of  oil  being  carried  in  the  remainder  of  the  ship. 

Between  the  oil  tanks  and  the  remainder  of  the  ship  it  is  con- 
sidered necessary  to  place  a  coffer-dam.  In  a  tank  steamer 
the  rest  of  the  ship  means  the  engine  and  boiler  compartments. 
This  coffer-dam  is  two  transverse  stiffened  bulkheads  extending 
across  the  ship  and  properly  filled  with  water  as  a  safeguard 
against  leakage  of  oil.  In  practice  this  coffer-dam  is  often 
filled  with  fuel  oil,  a  practice  upon  which  doubts  may  be  ex- 
pressed, for  apparently  this  destroys  much  of  the  safety  in- 
tended to  be  given.  Oil  fuel  is  also  carried  in  the  double 
bottom  below  the  engine  compartments,  which  again  is  a  point 
open  to  discussion,  for  a  vessel  might  be  so  injured  by  going 
aground  as  to  flood  the  boiler  compartment  with  oil  with  risk 
of  explosion. 

It  is  safer  practice  to  exclude  oil  from  both  the  power  com- 
partment bottoms  and  from  the  coffer-dams,  the  latter  being 
kept  perhaps  narrower  than  they  are  now. 

Where  the  oil  is  of  a  specially  heavy  class,  there  might  not 
be  much  risk  if  it  did  leak  into  the  firehold,  and  good  residuum 
or  astatki  would  be  something  of  a  safeguard  between  the 
main  tanks  of  crude  oil  and  the  boiler  room.  Be  this  as  it 
may,  the  presence  of  a  narrow  water  space  outside  the  oil 
fuel  coffer-dam  gives  a  better  margin  of  safety. 

The  riveting  of  oil-tight  plating  is  usually  3  to  3J  diameters 
in  pitch.  Old  ships,  to  be  rendered  fit  for  oil  carrying,  which 
have  rivet  spacings  of  7  to  8  diameters,  may  thus  have  a  new 
rivet  put  into  each  spacing.  Such  ships  usually  require 
additional  deck  beams,  as  a  rule.  Ships  should  have  not  less 
than  eight  water-tight  compartments,  and  the  separating 
bulkheads,  if  oil  tanks,  ought  to  be  connected  directly  to  the 
skin  of  the  ship,  all  possible  empty  spaces  being  avoided.  Oil 
is  filled  into  tanks  so  as  to  stand  2  feet  above  the  upper  deck 
level  in  the  expansion  trunks.  The  gases  driven  off  from  oil 
are  heavy,  and  settle  at  the  bottom  of  any  space  into  which 
they  obtain  access.  Ventilation  is  required  to  get  rid  of  such 
gases.  Air  should  be  admitted  through  cowl  heads  to  the  upper 
part  of  the  place  to  be  ventilated  and  removed  from  the  lower 
part.  It  will  dilute  and  carry  off  the  accumulated  gas.  Such 
air  outlets  should  have  induction  openings  to  assist  the  current. 
The  general  direction  of  air  movement  in  a  ship  is  from  aft 
forward,  and  advantage  may  be  taken  of  this  in  arranging  the 
ventilation. 


OIL  FUEL  AT   SEA  129 

Great  care  is  needed  to  joint  all  oil  pressure  pipes  carefully. 
The  screw  threads  should  be  good,  and  ought  to  make  tight 
joints  with  only  a  little  smear  of  litharge  and  glycerine,  or 
Venetian  red  and  shellac.  Pipes  must  not  be  concealed  be- 
neath floor  plates,  in  bilges,  or  behind  casings,  but  ought  to 
be  fully  exposed  to  view. 

An  oil  cargo  being  so  easily  mobile  with  movement  of  the 
ship,  it  is  necessary  that  the  tanks  should  be  full,  so  that  there 
may  be  no  surging.  Hence  the  use  of  expansion  trunks  to 
permit  of  this,  and  allow  expansion  without  waste  or  pressure 
being  the  result.  Surging  plates  must  be  employed  in  those  com- 
partments, which  may  not  be  always  full,  as  the  fuel  tanks,  and 
no  compartment  should  occupy  too  much  of  the  length  of  a  ship 
without  a  bulkhead.  Similarly  bulkheads  are  stiffened  from 
one  to  the  other  by  longitudinal  plates,  which  check  transverse 
surging,  or  scending.  The  ordinary  cargo  boat,  when  fitted  for 
fuel  oil,  is  re-riveted  when  necessary,  and  the  oil  fuel  is  carried  in 
the  double  bottom,  and  can  be  replaced,  as  consumed,  with 
water  ballast.  Oil  is  also  carried  in  the  fore  and  aft  peaks. 

Oil  Steamers. 

One  of  the  best  examples  of  an  oil  steamer  is  the  s.s.  Trocas, 
which  has  been  fitted  for  liquid  fuel  by  the  Wallsend  Slipway 
and  Engineering  Company,  Ltd.,  the  system  adopted  being 
the  Flannery-Boyd  with  Rusden  &  Eeles  burners. 

The  ship  is  an  oil-carrying  vessel  of  347  feet  in  length  and 
45-7  feet  beam,  and  at  full  load  carries  6,000  tons  of  oil. 

One  of  the  greater  obstacles  in  the  way  of  fitting  old  steamers 
with  liquid  fuel-burning  arrangements  is  the  difficulty  of  con- 
structing suitable  spaces  to  carry  the  liquid  fuel.  Ordinary 
coal  bunkers  are  of  course  not  suitable,  as  the  riveting  and 
plating  is  not  oil-tight.  In  the  Flannery-Boyd  system  the 
oil  is  carried  in  all  the  ballast  tank  spaces  throughout  the  ship, 
namely,  the  fore  and  aft  peaks,  the  double  bottom  ballast  tanks 
under  the  engines  and  boilers,  the  forward  ballast  tank  adjacent 
to  the  fore  peak,  and  the  forward  and  aft  coffer-dam. 

The  main  difficulty  in  carrying  liquid  fuel  in  these  spaces 
is  that  some  water  always  remains  in  a  ballast  tank,  owing  to 
the  difficulty  of  completely  draining  it.  This  water  becomes 
mixed  with  the  liquid  fuel,  and  passing  to  the  burners  causes 
dangerous  explosions,  and  generally  puts  out  flame.  It  is 
therefore  necessary  to  eliminate .  the  water.  To  do  this  two 
settling  tanks  of  large  capacity  are  placed  in  the  'tween  decks 
amidships,  adjacent  to  the  boiler  room  bulkhead.  These  tanks 


130         LIQUID  FUEL  AND  ITS  APPARATUS 

are^fitted  with  heating  coils  to  enable  the  liquid  fuel  to  be 
heated  to  a  sufficient  temperature  to  allow  of  the  water  freely 
separating.  The  water  then  settles  to  the  bottom  of  the  tank, 
and  can  be  drained  off. 

Each  tank  is  made  of  sufficient  size  to  contain  half  a  day's 
supply,  so  that  half  a  day  is  allowed  for  the  water  to  become 
separated.  From  these  separation  or  service  tanks  the  oil 
gravitates  to  the  burners,  and  is  sprayed  by  a  jet  of  steam. 

Each  furnace  is  fitted  with  two  burners,  and  the  furnace 
arrangements  are  such  that  the  complete  coal  burning  gear 
remains  intact  when  burning  liquid  fuel,  so  that  the  system  of 
either  coal  burning  or  liquid  fuel  burning  can  be  resorted  to  at 
wiU. 

If  the  vessel  is  burning  liquid  fuel,  and  it  is  found  necessary 
from  economical  reasons  to  resort  to  coal  burning,  it  is  only 
necessary  to  rake  a  few  broken  fire-bricks  from  the  bars  and 
disconnect  the  burners  and  light  a  coal  fire.  This  operation 
can  be  carried  on  without  stopping  the  vessel  at  sea  ;  the 
whole  operation  in  a  large  vessel  can  be  carried  out  within  an 
hour. 

The  s.s.  Trocas  has  three  large  single-ended  boilers  and  one 
donkey  boiler.  The  large  boilers  have  each  three  furnaces, 
and  the  small  boiler  has  two  furnaces.  All  are  fitted  for  liquid 
fuel. 

The  question  of  safety  and  flash-point  is  of  importance. 
The  British  Admiralty  did  require  a  flash-point  of  270°F., 
but  now  accept  a  minimum  of  175°:  Lloyds'  register,  of  200°, 
now  reduced  to  150°,  while  the  German  authorities  have 
accepted  as  safe  150°.  Fuel  of  the  lower  flash  has  been  in 
constant  use  for  four  years  in  British  and  Dutch  mercantile 
vessels,  with  complete  immunity  from  accident.  It  is  not 
desirable  to  fix  a  flash-point  higher  than  is  really  necessary  for 
safety,  because  high -flash  points  are  obtained  by  removing 
the  more  volatile  parts  of  the  liquid,  so  as  to  leave  a  thick 
and  sluggish  residuum,  which  requires  much  power  to  pulverize 
it.  The  London  County  Council  ask  for  150°.  ^ 

Comparative  Advantages  for  War  Vessels. 

Sir  Fortescue  Flannery  says  :  The  problem  that  confronts 
every  designer  of  a  warship  is  the  combination  of  the  maximum 
speed,  armament,  ammunition  supply,  protection,  and  range 
of  action  in  the  smallest  and  least  expensive  hull,  and  any 
reduction  of  weight  and  space  of  these  is  a  saving  which  acts 
and  reacts  favourably  upon  the  problem.  The  comparisons 
between  coal  and  oil  fuel  realized  in  recent  practice  are  that 


OIL  FUEL   AT  SEA  131 

2  tons  weight  of  oil  are  equivalent  to  3  tons  weight  of  coal,  and 
36  cubic  feet  of  oil  are  equivalent  to  67  cubic  feet  of  coal  as 
usually  stored  in  ships'  bunkers  ;  that  is  to  say,  if  the  change 
of  fuel  be  effected  in  an  existing  war  vessel,  or,  applied  to  any 
design  without  changing  any  other  of  the  data  than  those 
affecting  the  range  of  action,  the  range  of  action  is  increased 
50  per  cent,  upon  the  bunker  weight  allotted,  and  nearly  90 
per  cent,  upon  the  bunker  space  allotted. 

"  The  coal  protection  of  cruisers,  if  an  advantage — a  matter 
of  opinion — would  disappear  with  the  use  of  liquid  fuel,  because 
it  would  be  for  the  most  part  stowed  below  the  water  line,  if 
not  wholly  in  the  double  bottom. /The  double  bottom  and 
other  spaces,  quite  useless  except  for  water  stowage,  would  be 
capable  of  storing  liquid  fuel,  and  the  space  now  occupied  by 
coal  bunkers  would  be  available  for  other  uses. 

"  The  ship's  complement  would  be  reduced  by  the  almost 
complete  abolition  of  the  stoker  element  and  the  substitution 
of  men  of  the  leading  stoker  class  to  attend  to  the  fuel  burners 
under  the  direction  of  the  engineers,  and  the  space  of  stokers' 
accommodation,  their  stores  and  maintenance,  would  be  saved. 
The  number  of  lives  at  risk  and  of  men  to  be  recruited  and 
trained  over  a  long  series  of  years  would  be  reduced,  without 
reducing  the  manoeuvring  or  offensive  or  defensive  power  of 
vessels  of  any  class  in  the  fleet.  • 

"  Re-bunkering  at  sea — so  anxious  a  problem  with  coal — 
would  be  made  easy,  there  being  no  difficulty  in  pumping  from 
a  store  ship  to  a  warship  in  mid-ocean  in  ordinary  weather. 
Three  hundred  tons  an  hour  is  quite  a  common  rate  of  delivery 
in  the  discharge  of  a  tank  steamer's  cargo  under  ordinary 
conditions  of  pumping. 

"  The  many  parts  of  the  boiler  fronts  and  stokehold  plates, 
now  so  quickly  corroded  by  the  process  of  damping  ashes  before 
getting  them  overboard,  would  be  preserved  by  the  action 
of  the  oil  fuel,  and  the  same  remark  applies  to  the  bunker 
plating,  which  now  so  quickly  perishes  by  corrosion  in  way  of 
the  coal  storage. 

"  Liquid  fuel,  if  burned  in  suitable  furnaces  with  reasonable 
skill  and  experience  on  the  part  of  the  men  in  charge,  is  smoke- 
less. It  is  easy  to  produce  smoke  with  it,  but  this  is  evidence 
of  its  being  forced  in  combustion,  or  of  the  detailed  arrange- 
ments of  the  furnace  being  out  of  proper  proportion  to  each 
other.  In  regard  to  smokelessness,  it  is,  when  used  under 
conditions  customary  in  the  merchant  service,  not  inferior  to 
Welsh  coal,  and  superior  to  any  other  coal  ordinarily  in  use. 

"  The  cost  of  oil  in  the  East  is  less  than  the  cost  of  Welsh 


132          LIQUID  FUEL  AND   ITS  APPARATUS 

coal  when  the  cost  of  transport  and  Suez  Canal  dues  are  added 
to  the  original  price  of  coal  as  delivered  in  a  Welsh  port." 

It  is  only  since  Texas  oil  has  been  discovered  that  the  success- 
ful competition  of  oil  has  appeared  probable  to  the  west  of  the 
Suez  Canal.  In  the  mercantile  marine  advantage  is  gained 
by  a  reduction  of  the  stokehold  complement,  a  crew  of  thirty- 
two  being  reducible  to  eight. 

Fast  Atlantic  liners  find  it  difficult  to  get  coal  to  their  boilers 
for  the  firemen  to  burn,  and  they  lose  time  in  consequence,  even 
when  their  engines  and  boilers  are  in  perfect  order.  This 
difficulty  disappears  with  oil,  and  there  is,  a  saving  of  space 
previously  occupied  by  men  and  stores. ' 

Allowing  3  tons  of  coal  to  be  equal  to  2  tons  of  oil,  a  first-class 
Atlantic  liner  will  gain  1,000  tons  for  freight,  as  well  as  the 
whole  of  the  bunker  space.  That  is,  with  oil  in  the  peaks 
and  ballast  tanks,  there  will  be  a  gain  of  100,000  cubic  feet  of 
paying  space,  and  for  most  ships  at  least  a  fourth  of  the  coal 
bunker  space  could  be  used  for  cargo.  There  is  in  addition 
the  saving  in  time  when  coaling.  Oil  is  pumped  in  without 
the  help  of  a  man.  No  fires  require  to  be  cleaned  ;  there  are 
no  ashes  to  be  removed.  / 

Fires  made  by  oil  are  perfectly  steady,  the  steam  pressure  is 
constant,  while  the  temperature  of  the  stokehold  in  steamships 
is  lower,  since  the  furnace  doors  are  never  opened  and  hot 
cinders  are  not  pulled  out  into  the  room.  / 

The  loss  of  heat  up  the  stack  is  reduced  owing  to  the  clean 
condition  of  the  tubes  and  to  the  smaller  amount  of  air  which 
has  to  pass  through  the  furnaces  for  a  given  calorific  capacity 
of  fuel,  and  there  is  a  more  equal  distribution  of  heat  in  the  com- 
bustion chamber,  as  the  doors  do  not  have  to  be  opened  ;  con- 
sequently there  is  a  higher  efficiency.  The  heat  is  easier  on 
the  metal  walls  of  the  boiler,  being  better  diffused  over  the 
whole  surface. 

The  cost  of  handling  fuel,  by  pumps,  is  reduced. 

No  firing  tools  or  grate  bars  are  used,1  to  damage  the  furnace 
Hning. 

No  dust  fills  the  tubes  to  diminish  the  heating  surface. 

The  fire  can  be  regulated  from  a  low  to  an  intense  heat  in 
a  short  time.  / 

Many  factories  in  Pennsylvania  and  Ohio  had  to  increase 
their  boiler  capacity  by  about  35  per  cent,  when  returning  to 
the  use  of  coal  on  account  of  the  high  cost  of  oil. 

1  Grate  bars  may  be  employed,  under  certain  conditions,  as  explained 
elsewhere. 


CHAPTER    VIII 

MARINE   FURNACE    GEAR 

r  I  ^HE  use  of  steam  or  of  air  for  atomizing  is  a  mixed  ques- 
A  tion.  Steam  is  more  convenient,  and  is  naturally  first 
used,  but  it  becomes  so  severe  a  drain  on  the  fresh  water  supply 
that  it  is  practically  inadmissible  at  sea. 

The  claim  that  its  oxygen  is  set  free  by  the  fire  and  burned 
with  advantage  to  the  evaporative  efficiency  of  the  boiler 
cannot  be  allowed.  The  dissociation  of  water  or  steam  absorbs 
exactly  as  much  heat  from  the  fire  as  is  given  back  by  the  re- 
combination. 

Some  makers  of  atomizing  apparatus  claim  to  secure  a  softer 
flame  with  steam,  but  so  far  as  our  chemical  and  physical 
knowledge  extends,  air  ought  to  be  superior.  It  requires, 
however,  to  be  first  compressed,  and  it  is  desirable  that  it 
should  be  heated  to  near  the  oil  flash-point,  so  that  the  oil  may 
burn  freely  as  soon  as'  atomized. 

Ships  in  the  Caspian  Sea  use  steam,  but  are  never  far  from 
land.  Fuel  may  be  injected  under  pressure  and  break  up  against 
an  obstacle  at  the  furnace  mouth,  or  it  may  be  vaporized  by 
heat  before  reaching  the  furnace  mouth. 

In  Mr.  Howden's  modification,  fuel  is  injected  under  pressure 
mixed  with  air  previously  heated  by  the  waste  chimney  gases, 
and  this  system  has  been  fitted  to  the  North  German  Lloyd 
steamers  Tanglier  and  Packman ;  by  Workman,  Clark  &  Co;, 
of  Belfast. 

In  the  s.s.  Murex  already  named,  which  arrived  in  the  Thames 
in  the  spring  of  1902  from  a  voyage  of  11,800  miles,  from  Singa- 
pore via  the  Cape,  the  furnaces  were  never  touched.  Her  coal 
consumption  averaged  25  tons  per  day.  With  oil  fuel  the  daily 
consumption  is  16  tons  only.  The  fuel  supply  arrangements, 
Fig.  9,  consist  of  steam  pipes  A  A  A  A,  oil  pipes  B BB B,  and 
burners  C  C  C  C,  hung  on  swivels  D,  so  as  to  be  adjustable  in 
position,  and  to  allow  the  doors  to  open  upon  the  same  axis  or 
hinge  centre.  Coal  can  be  reverted  to,  when  the  burner  orifices 
F  F  F  F  are  closed  by  the  pivoted  slides.  In  Fig.  10  is  shown 

133 


134         LIQUID  FUEL  AND  ITS  APPARATUS 

the  brick  work  H  H  in  the  form  of  pillars  and  arches  against 
which  the  flames  first  impinge.  At  K  K  are  further  baffle 
bridges  to  keep  the  flame  from  too  severely  striking  the  back  of 
the  combustion  chamber  carrying  the  stay  nuts,  the  tube  ends, 
rivet  seams  and  parts  liable  to  injury  from  excessive  local  heat. 
The  form  of  burner  is  the 

Eusden-Eeles 

type,  Fig.  67,  with  adjustable  annular  orifices  both  for  steam 
and  oil  (see  Chapter  XIX).  They  possess  the  quality  of  ad- 
justability while  at  work  essential  to  secure  the  most  perfect 


Fig.  9.     FURNACE  FRONTS  or  s.s.  "  MUREX." 

possible  conditions  of  combustion.  The  oil  annulus  is  sur- 
rounded by  a  steam  jacket,  and  steam  enters  the  middle  cham- 
ber and  escapes  into  the  furnace  round  the  central  stem,  which 
is  drawn  back  by  revolving  the  end  wheel  and  allows  an  annular 
spreading  steam  jet  to  escape  round  the  flaring  end  of  the 
stem.  Oil  finds  its  way  to  the  little  ring  chamber  immediately 
at  the  nozzle,  and  is  directed  down  the  sloping  ends  of  the  slide 
directly  upon  the  steam  jet  which  pulverizes  it  and  spreads  it 
in  the  furnace.  The  oil  slide  is  drawn  back  by  rotating  the  larger 
handle. 

Interchange  of  Coal  and  Oil. 

To  permit  the  ready  interchange  of  coal  and  oil  the  s.s.  Trocas 
with  fitted  as  in  Fig.  11,  the  coal  grates  remaining  and  being 


MARINE  FURNACE  GEAR 


135 


covered  with  8  inches  of  broken  brick.     The  brickwork  B,  Gy 
and  D  always  remains  in  place. 

To  change  over  from  oil  to  coal  the  burners  are  swung  back 
to  clear  the  furnace  door,  the  broken  brick  is  raked  out,  and 


I  ,   I 


Fig.   10.     ARRANGEMENT  OF  FURNACE  BRICKWORK,  s.s.  "  MUREX." 


ordinary  coal  firing  resumed.  In  twenty-eight  minutes  after 
steaming  full  speed  under  oil  the  Trocas  was  again  at  full  speed 
under  coal. 

It  is,  however,  found  as  the  result  of  experience  of  long 
voyages  that  it  is  better  not  to  let  the  firebars  remain  in  when 


136         LIQUID  FUEL  AND  ITS  APPARATUS 

using  oil,  for,  at  the  worst,  the  change  over  can  be  made  in  a 
few  hours,  and  better  results  obtained  from  oil  with  the  more 
approved  arrangement.  The  general  arrangement  of  the  s.s. 
Trocas  is  that  of  Fig.  10. 

It  is  estimated  by  Sir  Fortescue  Flannery  that  the  atomizing 
steam  will  amount  to  0-2  pound  per  i.h.p.  per  hour.  The  waste 
is  made  up  by  large  evaporators,  usually  in  three  interchange- 
able sections  which  should  be  worked  steadily. 

Two  burners  in  each  furnace  are  found  to  give  better  results 
than  one  larger  burner,  being  more  easily  adjustable  and 
maintaining  continuity  of  flame.  There  is  also  greatly  dimin- 


Fig.  11.     FURNACE  ARRANGEMENT  OF  s.s.  "TROCAS." 


ished  chance  of  extinguishment  of  the  flames  by  an  accidental 
access  of  water  from  imperfectly  dried  oil. 

The  Flannery-Boyd  System  for  Steamships. 

The  chief  object  of  the  system  is  to  separate  from  the  oil 
fuel  the  water  which  may  have  become  mixed  with  it  in  any 
manner  and  also  to  enable  oil  fuel  to  be  carried  in  ballast  tanks 
or  other  compartments  where  water  is  usually  carried. 

To  get  rid  of  the  water  two  or  more  settling  tanks  are  used, 
in  which  the  oil  remains  a  sufficient  length  of  time  to  permit 
of  the  water  depositing.  In  each  tank  is  a  heating  apparatus 
to  assist  the  action,  for  by  heating  the  oil  the  water  is  more 
quickly  deposited,  owing  to  the  expansion  of  oil  being  greater 
than  that  of  water,  and  because  the  oil  is  made  less  viscous  by 


MARINE  FURNACE  GEAR 


137 


heat.  Two  or  more  tanks  must  be  used,  so  that  while  the 
water  is  being  deposited  in  one  tank  the  dried  oil  in  the  other 
may  be  fed  to  the  burners.  The  system  is  applicable  to  any 
system  of  burning  oil. 


Oil.    FUEL 

op        SER^ICC 
ON      THE 
Boyo       PHTE.NT 


N.B.  SERWCE  TANKS  NUMBER  2  MAY  BE  MADE  ROUND,  SQUARE  OR  BUILT  INTO  SHIB 


SUCTION    PIPC  raui-i  BULLBST 


Fig.   12. 


Fig.  12  shows  the  various  pipe  arrangements,  the  oil  feed 
pump  3  drawing  from  the  ballast  tank  1  through  a  pipe  4 
and  delivering  by  pipes  5  to  the  service  tanks  22,  whence  the  oil 
gravitates  by  way  of  pipes  7  to  the  oil  burner  supply  pipes  9. 


i  I 


bC 

S 


138 


MARINE  FURNACE  GEAR 


139 


Overflow  pipes  13  carry  back  any  surplus  oil  to  the  main  tanks, 
and  separated  water  is  discharged  by  pipes  12. 

The  service  pipes  are  kept  free  of  pressure  by  vent  pipes  14, 
carried  up  several  feet. 

The  general  arrangement  of  an  oil  ship  is  shown  by  a  fairly 

MIDSHIP    SECTION. 


poqp_  D_« 


CONTINUOUS 
TftUHK   SIDE. 


EXPANSION 
OIL      TRUHK 

MAIN     D« 


OILTIGHT 
CENTRE  LINE 
BULKHEAD'. 


Fig.  13a.     MIDSHIP  SECTION  OF  OIL  TANK  S.S.  NEW  YORK. 

recent  example,  the  s.s.  New  York,  Figs.  13, 13a,  built  by  the 
Palmer "s  Shipbuilding  and  Iron  Company,  Ltd.,  of  Jarrow-on- 
Tyne.  In  this  class  of  vessel  all  the  seams  and  butts  of  the  shell 
plating,  decks,  and  bulkheads  are  riveted,  and  the  rivets  are 
spaced,  for  oil  tightness,  3|  diameters  centre  to  centre,  instead 


140         LIQUID  FUEL  AND  ITS  APPARATUS 

of  4  diameters  as  required  for  water-tight  work.  Special  care  is 
also  taken  to  avoid  as  far  as  possible  any  rivet  passing  through 
more  than  two  thicknesses  of  plating.  The  vessel  is  divided 
into  eight  pairs  of  oil  tanks  with  expansion  trunks  for  each  pair. 
There  is  a  coffer-dam  at  the  back  of  No.  1  tank,  separating  it 
from  the  power  department.  A  small  hold  for  miscellaneous 
cargo  is  placed  forward  by  No.  8  tank,  from  which  it  is  separated 
by  a  coffer-dam.  The  oil  tanks  are  divided  along  the  centre 
line  of  the  vessel  by  an  oil-tight  bulkhead,  so  that  there  are 
really  sixteen  oil  cargo  tanks.  The  length  of  the  New  York  is 
428  feet  between  perpendiculars,  the  breadth  54  feet  6  inches, 
and  the  depth  32  feet.  The  water  ballast  tanks  extend  the  full 
length  of  the  ship  below  the  oil  tanks.  Coal  bunkers  are  pro- 
vided on  each  side  of  the  engine  and  boiler  compartments 
and  also  forward  of  the  boilers,  between  the  boiler  compart- 
ment and  the  after  coffer-dam. 

The  Orde  System. 

In  Figs.  14,  14a,  15,  are  shown  various  arrangements  of  oil 
fuel  burning  by  Sir  W.  E.  Armstrong,  Whitworth,  and  Co.,  of 
Newcastle-on-Tyne,  according  to  the  system  of  Mr.  C.  E.  L. 
Orde. 

Fig.  14  shows  the  general  arrangement  for  a  water  tube 
boiler.  Steam,  superheated  in  the  casing  by  means  of  a  pipe 
carried  round  the  steam  dome,  is  taken  to  a  subsidiary  steam 
header,  whence  branch  pipes  issue  to  five  separate  burners. 
Oil  is  fed  by  similar  pipes  from  a  second  header  supplied  from 
the  bunker  or  oil  tank  through  a  heater  on  the  right.  This 
contains  exhaust  steam,  and  heats  the  oil  on  its  way  to  the 
burners.  The  oil  is  drawn  off  from  the  tank  as  in  Fig.  14a,  by 
means  of  a  floating  arm,  which  always  takes  the  highest  oil  from 
an  area  which  is  heated  by  a  steam  pipe  coil  placed  under  the 
intake  of  the  oil  pipe.  A  small  pump  forces  the  oil  to  the  distri- 
bution system,  a  relief  pipe  carrying  any  excess  back  to  the 
pump  suction.  Air,  heated  in  the  ashpit  through  which  the 
pipe  is  laid,  is  supplied  to  the  burners  by  a  separate  pump  on 
the  left.  The  copper  steam  pipe  to  the  float  is  flexible  to  allow 
for  the  float  movement,  and  the  float  is  kept  steady  laterally 
by  a  piece  of  angle  iron  bent  to  a  circular  form  to  suit  the  path 
of  the  float  arm.  Blow- through  steam  pipes  are  fitted  for 
clearing  the  oil  pipes  when  required.  The  atomizer,  Fig.  15, 
is  triple,  oil  entering  through  the  centre  passage,  with  needle 
regulating  spindle.  Steam  comes  outside  the  oil  through  an 
annular  passage  and  air  is  introduced  outside  the  whole,  the 


ofttbter  Separating  Apparatus. 

Fig.  14a.     FUEL  OIL  BUNKER.     DRAW-OFF  PIPE  AND  FLOAT. 


142 


MARINE  FURNACE   GEAR 


143 


mixture  being  blown  through  the  spreading  orifice  as  spray. 
The  oil  does  not  come  through  as  a  solid  jet  into  the  com- 
bining nozzle,  but  as  a  thin  annular  shell  jet  easily  atomized. 
The  atomizer,  however,  differs  from  some  others  which  admit 
air  at  the  centre.  The  illustration  shows  the  latest  pattern 
(1911). 

Highly  superheated  steam  is  intended  to  be  used  (preferably 
600°F.). 

The  annexed  table  from  a  paper  by  Sir  F.  Flannery,  in  the 
Transactions  of  the  Institution  of  Naval  Architects,  gives  a  few 
results. 


Ship. 

System. 

Oil  per 
I.H.P. 
per  hour. 

Coal     !  Heating 

IPHP.    ,  Sur£ace' 

i 

I.H.P. 

Per  cent, 
of  gain 
by  use 
of  Oil. 

F.  C.  Laeisz 
Sithonia     . 
Murex  . 

Syrian 
Khodoung  . 

Korting 
Howden     . 
Rusden- 
Eeles 

Ord'e     .      . 

Ib. 
1408 
1-065 
1-3 
16  tons  p.  d. 
1-32 
1-08 

Ib.        !     sq.  ft. 

1-93        7,560 
149        6,924 
25  tons     5,202 
per  day 
2,480 
1-67        2,700 

2,200 
2,500 

800 
960 

27-0 

28-6 
36-0 

35-5 

In  each  case,  except  the  Sithonia,  which  had  quadruple 
engines,  the  engines  were  triple  expansion. 

Lancashire  Boiler  with  Orde's  System. 

The  Lancashire  boiler  as  arranged  by  the  Wallsend  Slipway 
and  Engineering  Company,  for  burning  oil  with  or  without  a 
grate,  is  given  in  Fig.  16. 

A  single  injector  is  applied  to  each  furnace  door,  the  grate  is 
covered  with  broken  brick,  and  at  the  middle  of  its  length 
a  brick  baffle  is  built,  round  and  through  which  the  flames 
escape,  and  after  passing  a  low  bridge  at  the  rear  of  the  grate 
escape  unimpeded. 

Without  a  grate,  the  furnace  is  fitted  with  a  brick  oven  and 
striking  bridge,  beyond  which  is  a  cellular  baffle  of  brick 
which  gives  a  final  mixing  to  the  gases  before  they  are  quite 
consumed. 

A  gravitation  tank  is  placed  about  10  feet  above  the  level 
of  the  atomizers,  with  suitable  valves,  vent  pipe,  overflow  and 
gauge.  The  supply  pipe  to  the  atomizer  has  a  strainer  in  its 
course. 

These  various  arrangements  differ  very  little  from  those  of 
other  engineers,  the  chief  object  being  the  atomizing  and  the 
arrangement  of  the  fire-brick  oven  and  bridges. 


0/7 


Fig.  15.     ORDE  AND  SODEAU'S  ATOMIZER,  ARMSTRONG  WHITWORTH  &  Co. 


144 


8 


145 


146         LIQUID  FUEL  AND  ITS  APPARATUS 


The  Wallsend  System  of  Oil  Burning. 

In  the  latest  practice  of  the  Wallsend  Slipway  and  En- 
gineering Co.  the 
oil  is  injected  into 
the  furnaces  (Fig. 
17)  under  pressure 
by  m  eans  of 
pumps,  no  steam 
being  used  in 
atomizing  the  oil, 
but  only  steam  to 
drive  the  fuel 
pumps  and  to  heat 
the  oil  in  the 
heaters. 

After  the  steam 
has  done  its  work 
it  is  delivered  to 
the  condenser  and 
there  is  no  loss  of 
fresh  water. 

There  are  no  air 
compressors  o  r 
blowers  required, 
the  only  working 
parts  being  the  oil 
fuel  pumps  them- 
selves,  so  that 
wear,  tear  and 
breakdowns  are 
reduced  to  a  mini- 
mum. 

The  liquid  fuel 
is  drawn  from  the 
storage  tanks  by 
duplex  pumps. 
On  its  way  to  the 
pumps  the  oil 
passes  through  a 


duplex  filter,  ar- 
ranged that  each 
side  can  be  cleaned 
whilst  the  other 
side  is  in  use. 


MARINE  FURNACE  GEAR  147 

The  pump  delivers  the  oil  first  to  a  receiver  of  sufficient 
capacity  to  ensure  its  discharge  to  the  burners  under  a  steady 
pressure.  From  the  receiver  the  oil  passes  through  the  main 
steam  heater. 

The  temperature  of  the  oil  on  leaving  the  heater  is  recorded 
and  the  oil  then  passes  through  a  discharge  duplex  strainer  of  a^ 
similar  design  to  the  suction  strainer  and  thence  to  the  burners 
(Fig.   18),  to  which  are  fitted  special  air  distributors.     These  ,' 
consist  of  an  inner  and  outer  cylinder  having  vanes  fitted   /l 
between  them. 

These  vanes  are  arranged  specially  and  give  a  rotatory 
motion  to  the  air  and  oil  spray. 

Two  sets  of  nozzles  are  supplied  to  allow  a  wide  range  of 
power  being  developed  by  the  boilers. 

The  air  distributors  are  adjustable  so  that  the  amount  of  air 
entering  the  furnaces  can  be  regulated  to  a  nicety  and  complete 
combustion  obtained. 

Tests  carried  out  on  this  system  by  Professor  Barr  on  Messrs. 
J.  Howden  &  Co.'s  works  boiler  at  Glasgow  showed  16-22  Ib. 
of  water  evaporated  per  Ib.  of  oil  burnt  from  and  at  212°F. 

As  a  result  of  Messrs.  J.  Howden  &  Go's  experience  with  the 
system  they  have  decided  to  fit  the  Wallsend  System  as  shown 
in  Fig.  17a  in  conjunction  with  their  closed  system  of  forced 
draught. 

In  this  and  Fig.  17  it  will  be  noticed  that  there  is  now  very 
little  brickwork  in  the  furnace  of  a  marine  boiler,  and  that  the 
whole  circumference  of  the  furnaces  is  available  as  heating 
surface. 

This  is  possible  with  the  fine  atomization  and  air  mixture, 
combustion  being  well  advanced  before  the  conical  spray  reaches 
the  furnace  plates.  When  there  are  no  firebars  the  whole  of 
the  furnace  surface  is  efficient  as  heating  surface  and  the  lower 
part  of  the  boiler  is  thus  kept  hotter  than  when  the  ashpit 
bottom  is  shielded  by  a  grate.  Each  spray  nozzle  has  its  sur- 
rounding annular  air  passage  with  whirl  vanes,  and  this  keeps 
the  outer  trunk  cool.  A  protecting  face  of  brickwork  is  em- 
ployed as  shown. 

The  annexed  table  gives  the  results  of  the  tests  above  re- 
ferred to  and  made  on  Messrs.  Howden's  works  boiler  of 
11  ft.  diameter  X  lift.  Gin.  long  with  two  39  inch  furnaces 
and  a  total  heating  surface  of  1,358  sq.  ft.  The  steam  was 
stated  to  be  dry,  or  nearly  so.1 

1  The  dryness  was  tested  by  calorimeter,  but  the  author  places  no 
reliance  on  any  known  system  of  taking  samples  of  steam  out  of  a 
steam  pipe.  The  sample  passed  to  the  calorimeter  cannot  be  known  to 
be  accurate. 


Fig.  18.     THE  WALLSEND  PRESSURE  BURNER. 


148 


MARINE  FURNACE  GEAR 


149 


It  will  be  noted  that  the  weight  of  oil  per  hour  figures  out  at 
nearly  46  Ib.  per  square  foot  of  cross  section  of  furnace 
in  trial  1,  and  31  Ib.  in  trial  2  with  lighter  draught. 
Reckoned  on  the  longitudinal  section  of  the  furnace  as  though 
each  furnace  had  20  sq.  ft.  of  grate  area,  as  it  might  have 
with  grates,  the  fuel  per  square  foot  per  hour  works  out 
at  about  23  and  16  Ib.  respectively,  or  a  heat  production  per 
square  foot  of  "  grate  "  of  about  the  equal  of  30  and  21  Ib.  of 
coal. 


SUMMARY  OF  RESULTS  OF  TRIALS  OF  THE  WALLSEND  PATENT 

LIQUID  FUEL  BURNING  SYSTEM  WORKING  WITH  HOWDEN'S 

FORCED  DRAUGHT. 


Duration  of  trial  .      .      .    hours 
Number  of  burners  per  furnace  . 
Class  of  oil  used    .      .     (Scotch) 
Calorific  value  (nett)  of  the  oil 
B.T.U. 
Specific  gravity  of  the  oil  at  60°F. 
Steam  pressure      .  Ib.  per  sq.  in. 
Average    temperature    of    feed 
water       deg.  F. 
Pressure  of  air  entering  furnaces 
in.  of  water 
Temperature  of  air  entering  fur- 
naces         deg.  F. 
Description  of  smoke  at  chimney 
top 

One  No.  18 
Pumpherston 

18,770 
0-868 
155 

115 

190° 
Verv  light  to 

2 
One  No.  16 
Pumpherston 

18,770 
0-868 
155 

120 

fin. 
185° 
Verv  light  to 

Temperature  of  gases  at  the  foot 
of  chimney   .      .      .      .deg  F 

none 

488° 

none 

420° 

Weight  of  oil  burned  per  hour  Ib. 
Weight  of  oil  burned  per  hour 
per  burner    Ib. 
Weight  of  water  evaporated  per 

932 
466 
13  050 

633 
316-5 
9  000 

Weight  of  water  evaporated  per 
Ib.  of  oil  burnt  .      .      .      .  Ib. 
Equivalent  evaporation  from  and 
at  212°F  Ib. 

14-00 
15-91 

14-22 
16-22 

Equivalent  evaporation  from  and 
at  212°F.  per  sq.  ft.  of  heating 
surface  per  hour      .      .      .  Ib. 
Thermal  efficiency  of  boiler  . 

10-92 
82-3% 

7-55 

83-9% 

The  arrangement  of  the  Wallsend  System  to  a  marine  boiler 
of  Scotch  type  is  given  in  Figs.  19, 19a,  and  the  general  arrange- 
ment for  a  water-tube  boiler  is  given  in  Fig.  20. 


150 


161 


152         LIQUID  FUEL  AND  ITS  APPARATUS 

The  Korting  System. 

In  this  system,  as  fitted  to  the  Hamburg- American  s.s.  F.  C- 
Laeisz  several  years  ago,  the  water  was  first  separated  out  of  the 
oil  which  is  raised  by  a  pump,  and  heated  to  60°C.=  140°F. 
by  a  heater  on  the  suction  pipe,  and  filtered  before  it  reaches 
the  pump  valve,  and  thence  delivered  to  a  second  heater, 
which  raises  its  temperature  to  90°C.  =  194°F.,  and  after  a 
second  filtration  and  under  a  pressure  of  thirty  pounds  per 
square  inch,  injected  round  a  screwed  needle,  which  causes  the 
hot  oil  to  spray  itself.  The  bars  are  omitted,  and  the  furnace 
lined  in  fire-brick  and  the  air  is  admitted  through  adjustable 
perforated  gratings. 

The  front  of  the  oven  is  a  disc  of  fire-brick  with  a  small  open- 


Fig.  21. 


FURNACE  or  s  s.  "  F.  C.  LAEISZ,"  WITH  BRICKWORK. 
SYSTEM. 


KORTING 


ing  through  which  the  spray  is  delivered  and  air  is  admitted. 
It  this  system  the  oil  is  made  to  spray  itself  and  is  sufficiently 
atomized  by  the  pressure  and  the  action  of  the  screwed  needle 
round  which  it  escapes. 

The  furnace  of  s.s.  F.  C.  Laeisz  is  shown  in  Fig.  21  with  the 
furnace  lining  and  the  brickwork  of  the  combustion  chamber 
also.  In  Fig.  22  the  Korting  sprayer  is  shown  in  section,  with 
its  spirally  wound  needle  which  throws  the  oil  into  rapid  ro- 
tation and  causes  it  to  spread  widely  at  the  nozzle,  exactly  as 
in  the  case  of  the  Korting  water  cooling  sprayers.  It  was  then 
considered  essential  to  line  the  furnace  in  order  to  secure  perfect 
combustion  and  insure  that  all  the  oi]  is  vaporized  before  it 


MARINE  FURNACE  GEAR 


153 


reaches  the  chilling  zone  of  unprotected  water  cooled  plates, 
but  later  practice  by  the  Wallsend  Co.  appears  to  have  succeeded 
in    securing   com- 
bustion     without 
smoke   in  an   un- 
lined  furnace  as  in 
Fig.  17. 

The  diameter  of 
the  jet  orifice  is 
1  to  3  mm.,  and 
in  later  forms 
there  is  a  crown  or 
disc  set  round  the 
nozzle -and  pierced 
with  holes  of  1-25 
mm.  diameter, 

through  which  air  is  intrained.     The  output  under  a  pressure  of 
six  kilos  =84- 4  pounds,  was  as  follows  when  tried  at  Cherbourg — 

Orifice  ,      .      1  mm.  1  mm.  25         1  mm.  6 

Oil  per  hour  .      .      .     65  k.  100  k.  135  k. 

143  Ib.  220  Ib.  297  Ib. 

Tried  on  the  locomotives  of  the  Vladi-Kavkaz  Railway  these 
atomizers  with  double  jets  sprayed  230  kilos  =  506  Ib.  per 
hour  under  a  pressure  of  only  4-2  k.  =59-8  Ib.  From  the 


Fig.  22.     ROUTING  ATOMIZER. 


Fig.  22a.     ROUTING  ATOMIZER. 

trials  made  by  the  French  Navy  it  appears  that  these 
mechanical  atomizers  work  very  regularly  and,  moreover, 
silently,  if  the  oil  is  first  filtered  and  heated  to  80°C.  =  176°F. 
They  are  recommended  for  getting  up  steam,  the  force  pump 
being  hand  worked  until  such  time  as  steam  is  produced 
sufficiently  to  work  the  pulverisers. 

M.  Bertin  lays  stress  on  the  benefit  of  supplying  oil  to  a 
burner  at  a  considerable  pressure  and  at  a  high  velocity,  for 
even  with  air  or  steam  atomizers  the  fine  jet  will  atomize  more 
easily,  for  an  oil  pressure  of  three  kilos,  for  example,  permits  of 
a  velocity  four  times  as  much  as  is  given  by  a  head  of  2  metres. 


CHAPTER   IX 

LIQUID   FUEL  APPLICATIONS   TO   LOCOMOTIVE   BOILERS 

The  Holden  System. 

IN  this  system,  the  first  to  come  into  extensive  use  in  Great 
Britain,  the  object  has  been  to  combine  liquid  and  solid 
fuels  so  that  either  or  both  can  be  used  indifferently  without 
a  moment's  notice  of  the  change. 

Mr.  Holden,  of  the  Great  Eastern  Railway  of  England, 
primarily  devised  his  system  for  getting  rid  of  the  tars  pro- 
duced by  oil  gas  apparatus  ;  but  he  has  used  many  liquids  for 
fuel,  including  coal  tar,  blast  furnace  tar  and  oil,  shale  oil, 
creosote  and  green  oils,  astatki  and  crude  petroleum.  Loco- 
motives thus  fitted  are  clean  to  work,  make  no  dust,  smoke  or 
sparks,  have  little  wear  of  tubes  or  fire-boxes  and  have  little  ash 
and  clinker  to  remove.  Steam  can  be  raised  rapidly,  adjusted 
at  an  even  pressure,  and  waste  at  the  safety  valve  is  prevented. 
Any  boiler  can  be  fitted  for  liquid  fuel  without  alteration  of 
furnace,  though  it  is  desirable  to  add  a  fire-brick  lining  on  the 
tube  plate  below  the  arch. 

The  fire  is  made  up  thin  with  coal  and  about  120  pounds  of 
broken  fire-brick.  The  ashpit  damper  is  kept  sufficiently  open 
to  maintain  the  fire  bright. 

There  is  nothing  striking  to  be  seen  from  the  footplate,  with 
the  exception  of  an  extra  fitting  on  the  fire-box  casing,  carrying 
four  steam  cocks  and  two  small  wheel  valves  about  the  firedoor 
level  on  each  side  thereof. 

A  hinged  plate  appears  under  the  fire  door,  and  on  lifting  this 
there  are  visible  two  holes,  through  the  fire-box  outer  casing, 
leading  in  to  the  firebox,  and  equidistant  on  each  side  of  the  centre 
line  21  inches  apart ;  they,  are  5  inches  diameter  and  10  inches 
above  the  grate  surface.  In  each  hole  is  a  ring  of  pipe  per- 
forated on  the  front  side  so  as  to  direct  numerous  jets  of  steam 
forward  into  the  fire-box.  In  the  latest  atomizers  this  ring 
is  not  employed,  the  nozzle  of  the  atomizer  being  enclosed  in  a 
box  perforated  on  the  face  with  several  holes  through  which 

154 


APPLICATION  TO  LOCOMOTIVE  BOILERS     155 

the  spray  jets  issue  at  converging  angles.  These  cause  an 
induced  current  of  air.  In  the  centre  of  each  of  the  rings 
is  the  nozzle  of  an  injector.  These  are  steam  worked  and  inject 
oil  into  the  fire-box,  mixed  with  air,  which  enters  at  the  rear  of 
the  injectors  by  an  india-rubber  hose  connexion  from  the 
vacuum  brake  if  this  is  used. 

The  steam  inlet  to  each  injector  is  on  the  inside,  steam  com- 
ing by  a  single  pipe,  which  branches  off  by  square  turns  right  and 
left  to  the  injectors.  Oil  enters  by  separate  pipes  worked  by 
two  independent  regulating  wheel  valves,  which  stand  above 
the  footplate  at  the  fire  door  level.  Each  valve  is  thus  inde- 
pendently adjustable,  but  both  can  be  worked  together, 
instantly  to  open  and  close,  if  necessary,  at  stations  and  other 
stops.  Otherwise  the  oil  apparatus  is  controlled  from  the  four 
cocks  mentioned  above.  One  turns  steam  on  to  the  injector 
supply ;  another,  by  right  and  left  branch  pipes,  turns  steam 
to  the  air  injecting  rings ;  and  a  third  admits  steam  into  a 
warming  coil  in  the  oil  tank  for  the  purpose  of  bringing  the  oil 
to  a  state  sufficiently  liquid  to  flow  freely,  and  to  be  sprayed  suffi- 
ciently fine.  The  fourth  serves  to  blow  back  steam  through  the 
oil  fuel  pipes  to  the  tank  to  clear  any  obstruction  or  to  blow  back 
oil  which  has  cooled  in  the  pipe  or  to  warm  the  pipe,  and  to 
blow  through  the  oil  passages  of  the  injectors. 

The  mode  of  working  is  as  follows  :  the  engine  comes  up 
from  the  shed  with  the  light  coal  fire  with  which  steam  has 
been  made.  It  is  clear  and  red,  the  fire-brick  arch  well  heated, 
and  the  fire  made  up  with  brick  lumps  as  usual.  When  de- 
sired to  burn  oil,  steam  is  first  set  blowing  through  the  injector. 
The  delivery  of  the  injectors  is  directly  forwards  and  sideways, 
the  nozzle  having  two  orifices.  No  oil  is  sent  against  the  fire- 
box sides,  but  only  towards  the  brick  arch  and  towards  the 
middle  of  the  box,  the  two  inclined  jets  approaching  each  other. 
After  the  steam  is  turned  on,  the  oil  admission  valves  are  slowly 
opened  and  the  oil  is  sprayed  and  ignites  at  once,  the  whole 
firebox  being  filled  with  a  dazzling  white  flame. 

There  is  now  smoke  at  the  funnel  from  insufficient  air  supply. 
This  is  instantly  checked  by  turning  steam  into  the  ring  jets 
which  draw  in  a  further  large  quantity  of  air  through  the  five 
inch  openings,  and  smoke  can  be  reduced  to  any  extent  down 
to  nil.  This  is  a  specially  valuable  feature  in  economy,  for, 
while  it  is  so  desirable  to  prevent  smoke,  it  is  equally  unde- 
sirable to  admit  too  much  air,  and  this  can  be  regulated  to  a 
nicety,  merely  enough  air  to  stop  the  smoke  being  injected,  or 
even  only  enough  to  reduce  the  smoke  to  an  occasional  sus- 
picion of  it.  There  need  be  no  waste  due  to  excess  of  air. 


156         LIQUID  FUEL  AND  ITS  APPARATUS 

The  light  coalfire  is  kept  going  by  an   occasional  shovel  of 
coal. 

Though  the  apparatus  is  simple,  if  it  were  possible  for  it 
to  be  put  out  of  order  in  the  middle  of  a  trip,  the  fireman 
would  commence  to  shovel  coal  upon  the  existing  bed  of  fire, 
and  the  engine  would  run  as  an  ordinary  coal  burner  without 
a  hitch  or  stoppage. 

On  a  trip,  if  steam  is  high,  the  injectors  can  be  instantly 
stopped  on  arriving  at  a  station,  or,  if  the  steam  is  low,  con- 
tinued at  full  blast  as  when  running,  and  the  fire  kept  up  to  a 
maximum  efficiency,  and  steam  got  up  during  the  wait.  There 
is  less  dependence  on  the  blast  pipe,  and  a  variable  blast  nozzle 
is  used,  the  simple  movement  of  a  lever  in  the  cab  swinging  a 
hinged  cap  over  the  pipe  top  and  reducing  the  nozzle  from 
5J  to  4 1  inches  diameter  for  coal  burning. 

Should  any  oil  travel  unburned  so  far  as  the  brick  arch, 
and  even  run  down  it,  it  cannot  travel  over  the  firebrick  pro- 
tection of  the  lower  tube  plate  without  vaporization  and  com- 
bustion, hence  this  protection,  which  is  the  one  slight  difference 
from  common  practice,  a  difference,  however,  of  no  importance 
or  injury  to  the  engine's  coal  burning  properties. 

There  is  no  projection  of  any  oil  upon  the  fire-box  sides, 
neither  is  there  local  intense  combustion  to  produce  local  plate 
wasting.  On  the  contrary,  the  whole  interior  of  the  fire-box  is 
filled  with  flame,  and  no  special  ignition  point,  or  rather,  com- 
bution  area,  is  apparent.  Heating  is  therefore  general,  and 
temperature  even. 

Though  nominally  a  pound  of  oil  has  not  the  steam  making 
power  of  two  pounds  of  coal,  nor  perhaps  could  it  be  shown  to 
have  on  a  prolonged  test ;  yet  in  practice,  one  pound  of  oil  is 
found  to  be  equal  to  double  the  quantity  of  coal,  owing  to  the 
facility  of  regulation  and  the  saving  at  the  safety  valve  and  of 
the  back  pressure  from  reduced  blast  pipe  resistance.  Oil  has 
the  advantage  of  cleanliness  and  reduced  labour  all  round,  for  it 
makes  no  unconsumable  refuse,  requires  no  stoking  beyond 
the  keeping  up  of  the  small  bed  of  coal  fire,  which  seems  to 
be  a  good  system  where  liquid  fuel  supplies  are  doubtful  in 
quantity  and  uncertain  in  price,  over  any  system  of  oil  burning 
which  rejects  coal  entirely. 

In  the  ordinary  work  of  the  Great  Eastern  Railway  the  run 
between  London  and  Cambridge — about  56  miles — was  made 
with  one  firebox  full  of  coal  made  up  ready  for  the  run  and  un- 
touched. This  brought  the  train  to  its  destination,  and  if  it 
were  known  that  the  engine  would  be  shedded  at  once  the 
steam  might  be  pretty  well  reduced  and  the  fire  left  to  finish 


APPLICATION  TO  LOCOMOTIVE  BOILERS      157 

nearly  dead.  Here  came  in  the  advantage  of  liquid  fuel.  Even 
if  steam  was  down  and  the  fire  nearly  out,  the  turning  of  a 
1  andle  or  two  would  put  the  engine  in  readiness  to  take  out  any 
train  in  five  minutes  after  notice,  and  thus  an  engine  may  be 
worked  to  the  economy  it  would  be  if  about  to  be  shedded,  and 
yet  be  ready  for  a  full-power  run  almost  instantly. 

For  lighting  up,  however,  the  fire  started  in  a  clear  grate,  as 
usual,  and  the  month's  average  of  fuel,  including  lighting  up, 
was  12-2  pounds  of  oil  per  mile  and  11  pounds  of  coal,  or  a 
total  of  23-2  pounds  of  fuel.  Nine  other  engines  of  the  same 
class  and  the  same  range  of  duties  averaged  34  pounds  of  coal 
per  mile  for  the  same  month.  Thus  one  pound  of  oil  was 
practically  equivalent  to  two  pounds  of  coal. 

Mr.  Holden  states  that  for  oil  burning  to  be  a  success,  the 
apparatus  must  be  independent  of  any  firebox  alterations,  or 
of  anything  which  would  prevent  instant  return  to  coal  or 
solid  fuel,  or  its  use  in  Lighting  up.  Hence  his  special  injector 
to  spray  the  oil  without  the  use  of  special  brickwork,  hitherto 
common  as  a  means  of  giving  an  extended  hot  surface.  The 
several  small  ring  jets  which  converge  on  the  jet  of  oil,  both 
spread  and  mix  it  with  air  and  diffuse  the  flame,  so  preventing 
local  heating. 

The  injector,  of  gun  metal,  is  clearly  shown  in  section  in  Fig. 
23.  Oil  enters  at  the  side  some  way  back  of  the  steam  nozzle 
and  outside  this.  Steam,  therefore,  comes  inside  a  thin  ring  of 
oil  at  the  mixing  nozzle  and  through  the  inner  tube  comes  the 
vacuum  brake  air  which,  expanding  as  it  becomes  heated,  still 
further  aids  the  breaking  up  of  the  oil  into  spray.  The  ring 
jets  of  steam  induce  a  further  supply  of  air  on  the  exterior  of 
all,  and  so  is  obtained  an  alternation  of  air,  oil  and  air,  which 
promotes  admixture  and  thorough  combustion.  The  inside 
of  the  injector  is  removable  and  can  be  replaced  with 
a  spare  set  in  a  few  minutes  when  running.  Removal  of 
the  brake  hose  connexion  allows  the  injector  nozzle  to  be 
cleared  by  a  wire  while  actually  at  work,  this  being  the  main 
reason  of  the  through  passage  which  has  been  utilized — also 
for  the  purposes  of  the  vacuum  brake.  The  latest  atomizer  is 
that  of  Fig.  24  (1911).  Compared  with  Fig.  23  and  25  it  shows 
how  comparatively  little  change  has  been  made  in  the  last 
nine  years.  The  new  pattern  is  found  to  use  less  steam. 
The  ring  jets  of  this  pattern  (Fig.  25)  seemed  to  use  a  good 
deal  of  steam. 

In  the  newest  pattern  (Fig.  24)  there  is  a  small  box  end  enclos- 
ing the  nozzle,  and  the  flat  end  of  the  box  has  seven  perfora- 
tions inclined  to  each  other  so  as  to  give  a  converging  jet.  The 


158 


i   ill  CD  Hi? 

!©.:a~'- 


160          LIQUID  FUEL  AND   ITS  APPARATUS 

oil,  air  and  steam  are  mixed  in  the  box  and  issue  together. 
Small  supplementary  steam  jets  issue  from  small  holes  as 
shown  at  the  base  of  the  nozzle  box. 

The  brackets  of  the  oil  regulating  valves  are  movable  verti- 
cally. The  two  brackets  are  connected  to  a  hand  wheel  common 
to  both,  and  dropped  by  a  single  movement  of  the  wheel,  thus 
shutting  off  both  oil  valves  and  putting  them  again  in  action 
without  varying  their  individual  adjustment.  Later  arrange- 
ments differ  somewhat,  the  combined  motion  being  given  by  a 
lever,  as  in  Fig.  26. 

This  lever  is  used  for  the  station  stoppages,  after  which  each 
injector  can  be  set  going  again  exactly  as  before  the  stop,  so 
dispensing  with  fresh  regulation. 


Seciitn  A  3      Section  C  D 


'Fig.  25.     ATOMIZER.     OLD  FORM,  H.OLDEN  SYSTEM. 


In  locomotive  work,  the  absence  of  a  bed  of  incandescent 
fuel  on  the  grate  is  a  cause  of  very  serious  temperature  range 
in  the  firebox  when  the  oil  is  shut  off  at  stops.  Where  a  solid 
fire  is  maintained  on  the  combined  system,  there  is  always  an 
incandescent  fire  to  prevent  undue  cooling  when  the  oil  is 
stopped,  and  this  is  a  valuable  feature  apart  from  the  question 
of  lighting  up  in  the  ordinary  way  and  the  power  of  using 
solid  fuel  if  necessary  at  any  time  so  to  do. 

Fig.  24  is  the  latest  form  of  atomizer. 

The  valve  B  used  for  regulating  the  flow  of  the  oil  fuel  is  of 
special  construction,  found  desirable  after  many  attempts  with 
different  forms  of  cocks  and  valves.  To  pass  regular  quantities 
of  thick  viscous  fluid  through  the  "  crooked  passage  "  formed 
by  the  half  open  plug  of  a  common  cock  is  impossible,  and 
some  form  of  "  Straightway "  valve  is  necessary.  In  the 


162          LIQUID  FUEL  AND   ITS  APPARATUS 

example,  a  small  reservoir  of  oil  is  formed  by  the  body  of  the 
valve,  and  a  tube  with  a  slit  in  it  is  moved  up  and  down  inside. 
The  proportion  of  cut  exposed  in  the  oil  reservoir  regulates  the 
supply.  With  this  valve  very  fine  adjustments  in  the  flow  of 
oil  are  possible. 

The  Holden  apparatus  is  now  largely  used  on  stationary, 
locomotive  and  marine  boilers,  but  its  application  on  English 
railway  work  has  been  reduced  by  the  comparative  scarcity  of 
oil  since  the  demands  of  the  Navy  have  absorbed  so  much.  In 
short,  liquid  fuel  is  not  yet  produced  to  supply  the  demand. 

In  Fig.  27  is  shown  the  firebox,  about  8  feet  long,  of  an 
American  locomotive.  The  tube  plate  and  sides  are  lined  with 
brick,  and  there  are  two  air  inlets  at  the  bottom  of  the  box 
opening  into  the  ash  pit,  which  has  the  usual  front  and  back 
dampers.  In  these  narrow  boxes  there  is  only  room  for  one 
atomizer.  Oil  alone  is  intended  to  be  used  in  this  furnace,  and 
the  area  of  brickwork  is  necessarily  larger  than  in  the  mixed 
system,  where  the  bars  are  covered  with  more  or  less  self- 
incandescent  fuel.  The  fire-brick  arch,  but  slowly  adopted 
in  American  coal  burning  engines,  is  of  necessity  a  part  of  the 
oil  burning  furnace.  In  some  locomotives  there  is  also  a  small 
arch  over  the  atomizer  to  protect  the  fire  door.  In  certain 
locomotives  with  still  longer  boxes  there  will  be  a  wall  of 
brick  about  6  feet  in  front  of  the  atomizer,  and  the  arch  springs 
from  this  wall,  so  that  there  is  a 'combustion  space  between  the 
wall  and  the  tube  plate. 

With  Texas  oil  the  Great  Eastern  locomotives,  class  1900, 
have  hauled  fast  trains  on  a  consumption  of  24-7  pounds  of 
coal  tar  per  mile  plus  9-6  pound  of  coal  for  lighting  up,  etc.,  as 
against  40  to  45  pounds  of  coal.  On  a  test  run  with  a  train  of 
620  tons  a  four-coupled  passenger  engine  consumed  31  pounds 
of  Texas  oil  per  mile.  These  engines  were  fitted  with  air  heating 
arrangements.  On  the  Japanese  Government  railways,  Borneo 
oil  on  the  Holden  system  showed  an  evaporation  as  high  as 
14-42  and  averaged  12-6  the  year  round  as  against  6-4  pounds 
for  coal. 

An  important  item  is  the  lengthened  life  of  the  internal  fire- 
box. After  some  service  the  sides  of  an  ordinary  firebox 
present  a  series  of  convex  surfaces  between  the  stays,  which  are 
subjected  to  abrasion  by  the  small  ashes,  sparks,  etc.,  drawn 
from  the  fire  by  the  action  of  the  blast.  As  a  result  of  this 
wearing  away  of  the  surface  of  the  plate,  it  gradually  be- 
comes thinned,  and  eventually  cracks  develop  between  the  stay 
holes,  with  the  consequence  that  the  box  must  be  patched 
or  renewed  after  a  comparatively  short  existence.  With  oil 


APPLICATION  TO  LOCOMOTIVE  BOILERS      163 

fired  engines  an  extension  of  time  of  some  50  per  cent,  can  be 
secured,  as  no  such  destructive  action  exists.  These  remarks 
on  abrasion  apply  equally  to  the  tubes,  smoke  box,  chimney, 
etc.,  and  the  economies  in  this  direction  are  of  considerable 
value  when  large  numbers  of  locomotives  are  affected. 


Slope 


Slope 


Buiner 


Fig.  27.     FIREBOX  OF  AMERICAN  OIL-BURNING  LOCOMOTIVE. 

With  oil  burners  the  fire  is  of  equal  intensity,  and  as  clean 
at  the  end  of  the  day  as  at  the  start,  and  an  engine  can  be  run 
indefinitely  as  regards  the  fire. 

The  average  life  of  copper  fire-boxes  of  five  G.E.  Rly.  engines, 


164          LIQUID  FUEL  AND  ITS  APPARATUS 

No.  754  to  758,  with  coal,  was  found  to  be  5|  years,  and  that 
of  two  other  sister  engines,  No.  760  and  765,  using  liquid  fuel, 
was  respectively  8  years  4  months  and  8  years. 

In  fitting  these  burners  to  ordinary  stationary  boilers  they 
are  connected  by  means  of  pipes  to  a  hinged  joint  or  trunnion  so 
arranged  that  when  the  burner  is  swung  out  of  position,  the 
supplies  of  steam  and  oil  are  cut  off,  so  as  to  prevent  the  risk  of 
fires  in  the  stokehold. 

Where,  as  often  the  case,  oil  contains  water  in  such  quantities 
as  to  extinguish  the  fires  there  is  considerable  danger.  The  oil 
following  after  is — if  the  furnace  temperature  is  sufficiently 
high — violently  exploded,  or,  if  the  furnace  is  allowed  to  become 
too  cold,  the  oil  falls  through  the  ashpits  and  on  to  the  stoke- 
hold floor,  where  it  spreads  out  into  a  thin  film  probably  at  a 
temperature  approaching  the  flash  point,  and  therefore  in  a 
highly  inflammable  state. 

The  specific  gravity  of  most  fuel  oils  being  0-86  to  1  the  rate  of 
settling  at  low  temperatures  is  very  slow,  but  the  difference 
in  the  specific  gravity  becomes  much  more  marked  if  the 
temperature  is  raised,  and  very  usual  practice  has  been  to  heat 
up  the  whole  contents  of  the  oil  bunker  to  such  a  temperature  as, 
without  approaching  the  flash  point  of  the  oil,  will  make  the 
density  difference  sufficient  to  accelerate  the  settling. 

The  objection  to  this  is  that  a  large  amount  of  heat  is  required, 
the  radiation  surface  of  a  bunker  of  any  size  being  considerable  ; 
the  heating  process  is  slow,  and  unless  completed  before  any 
of  the  contents  are  drawn  off,  the  lower  layers  of  the  tank  will 
consist  either  of  pure  water  or  oil  with  a  large  percentage  of 
water  mixed  up  with  it. 

To  obviate  this,  a  floating  suction  is  used  consisting  of  a  long 
pipe  pivoted  upon  the  side  of  the  bunker  or  tank,  and  guided 
in  the  vertical  plane  by  means  of  a  tee  or  angle  iron  set  to 
correct  radius. 

The  suction  pipe  has  a  smaU  steam-pipe  led  along  its  side, 
which  terminates  in  a  coil  immediately  below  the  suction  open- 
ing. The  steam  passes  through  this  and  heats  the  oil  immedi- 
ately below  the  orifice,  and  this  oil  rises  into  the  pipe  and  leaves 
the  water  behind.  The  float  is  proportioned  and  arranged  to 
keep  the  mouth  of  the  pipe  about  6  inches  below  the  level  of 
the  oil  in  the  tank. 

This  apparatus  is  certain  in  action  and  requires  but  little 
heat,  since  this  is  only  applied  to  that  portion  of  the  oil  immedi- 
ately under  the  mouth  of  the  suction  pipe,  and  there  is  little 
radiation  from  the  bunker  side,  and  the  heated  oil  at  once 
moves  off  to  be  used  while  still  hot. 


About  20  barrow  loads  make  one  cubic  yard.     An  ordinary  cart 
holds  about    ||-  cubic  yard. 


165 


166         LIQUID  FUEL  AND  ITS  APPARATUS 

Fig.  28  shows  the  application  to  a  locomotive  with  fire-box 
3  feet  4J  inches  wide.  For  a  smaller  fire-box  one  atomizer  only 
is  necessary. 

The  apertures  in  the  fire-box  are  made  by  screwing  a  copper 
ferrule  into  the  tapped  plate  and  beading  over  at  the  ends  ; 
into  this  is  drifted  a  wrought  iron  ferrule,  which  makes  a  per- 
fectly tight  joint. 

The  nozzle  of  the  atomizer  is  placed  about  J  in.  above  the 
centre  of  the  aperture,  and  the  face  of  the  ring  f  inches  from 
the  front  of  same. 

When  liquid  fuel  is  used  alone,  steam  is  first  raised  in  the 
boiler  by  a  wood  and  a  coal  fire  to  25  pounds  or  30  pounds 
pressure,  the  fire  is  levelled  and  covered  with  a  layer  of  broken 
fire-brick  of  not  more -than  3  inches  cube,  spread  thinnest 
about  the  centre  of  the  fire-box,  and  well  packed  round  the 
sides  and  corners.  A  few  pieces  of  waste  or  wood  are  thrown 
in  to  cause  a  flame  before  the  fuel  is  introduced. 

An  air  heater  formerly  was  used,  but  has  been  abandoned  in 
recent  practice. 

The  regulating  gear  is  so  arranged  that  a  simple  movement 
of  the  lever  closes  both  oil  valves  without  affecting  their 
separate  adjustment  when  open. 


CHAPTER   X 

LIQUID  FUEL  APPLICATION  TO  STATIONARY  AND  OTHER  BOILERS. 

The  Lancashire  Boiler. 

FIG.  29  shows  the  arrangement  of  Holden's  Burners  on 
a  Lancashire  type  boiler.  The  burners  are  placed  at  the 
front  of  the  brick  lined  extensions,  to  which  heated  air  is  con- 
veyed from  large  tubes  passing  down  the  outer  flues.  The 
fire-brick  construction  is  simple  and  easily  introduced  for  an 
ordinary  sized  boiler  with  a  grate  of,  say,  7  feet  long.  A  strik- 
ing bridge  pillar  with  inclined  face  is  built  up  about  2  feet 
6  inches  inside  the  furnace  ;  next,  a  screen  with  large  clear 
opening  about  1  foot  6  inches  behind  the  former  ;  and  finally, 
a  second  screen  with  oblique  perforations  to  direct  the  gases 
along  the  inner  surface  of  the  flue.  The  central  portion  of  this 
last  screen  is  recommended  to  be  built  solid.  On  boilers  thus 
arranged,  with  fair  working  conditions,  an  evaporation  of  from 
14  to  15  pounds  of  water  per  pound  of  Texas  fuel  oil  (from  and 
at  212°F.)  is  readily  obtained. 

On  a  large  boiler  of  this  type  burning  north  country  "  smalls  " 
and  evaporating  only  6-5  pounds  of  water  per  pound  of  coal, 
the  Texas  fuel  oil  has  secured  an  evaporation  of  15-25  pounds  of 
water  per  pound  of  fuel. 

If  desired  the  fire  bars  are  left  in  and  covered  by  a  layer 
of  fire-brick  or  chalk  as  a  base  for  the  fire  in  case  it  may  be 
necessary  to  return  to  solid  fuel  at  any  time.  Any  internally 
fired  boiler  may  be  treated  by  either  method.  Where  the 
bars  are  left  in  there  ought  to  be  a  damper  fitted  to  the  opening 
of  the  ash-pit  to  regulate  the  admission  of  air. 

In  these  furnaces  the  injector  is  placed  about  8  or  10  inches 
above  the  grate  surface  and  about  J  inch  above  the  centre  of  the 
4-inch  opening  cut  through  the  furnace  door.  The  injector 
is  inclined  so  as  to  point  to  the  second  or  third  brick  from  the 
top  of  the  bridge.  Dry  steam,  perferably  superheated,  is 
admitted. 

Generally,  in  the  firing  of  internal  furnace  boilers,  the  fuel  is 
blown  in  parallel  with  the  grate  surface  and  8  to  10  inches 

167 


168 


ino 


170          LIQUID  FUEL  AND  ITS  APPARATUS 

above  it.  In  the  large  vertical  boiler  the  atomizer  is  usually 
placed  below  the  fire-door  opening,  but  in  small  vertical  boilers 
it  must  be  placed  through  the  door.  In  either  case  the  opposite 
half  circle  of  the  furnace  must  be  lined  with  fire-brick  to  the 
height  of  about  half  the  furnace  diameter  to  form  the  necessary 
incandescent  surface  on  which  any  unburned  oil  can  strike. 


The  Water  Tube  Boiler. 

For  the  water  tube  boiler  without  grate  bars  the  arrangement 
of  Fig.  30  is  employed,  there  be  in 3;  an  additional  arch  of  fire- 
brick brought  forward  from  the  bridge  to  prevent  too  early  a 
passage  of  the  gases  among  the  tubes.  The  author  would 
extend  this  (and  also  the  first  arch)  further  than  shown  in  Fig. 
30?  it  being  impossible  either  with  coal  or  oil  to  secure  smokeless 

results  where  the  hydrocarbon  gases 
,,<J^ I  pass  too  quickly  among  cold  tubes. 

/',/^f       '  Nor  is  there  space  and  time  for  such 

//'"/'  complete  combustion  as  is  desirable. 

The  steam  blast  may  be  made  less 
intense  when  oil  fuel  is  used  by  the 
Mac  Allan  movable  cap  (Fig.  31). 
This  is  folded  over  the  blast  pipe 
orifice,  which  it  reduces  from  5  J  to  4| 
inches  diameter. 

The  position  of  the  atomizer  is 
important.  If  too  high  the  combus- 
tion is  vibratory,  and  an  intolerable 
humming  sound  is  produced  by  the  many  rapid  explosions  due 
to  non-continuous  combustion.  The  oil  fire  must  be  along  the 
plane  of  the  coal  fire  for  the  best  results,  and  not  too  high 
above  it. 

Owing  to  its  large  proportion  of  hydrogen,  the  production 
of  carbon  dioxide  is  less,  and  this  is  held  to  be  an  advantage 
of  liquid  fuel  for  working  tunnels,  and  the  Arlberg  tunnel  was 
so  worked  by  32  engines.  It  must  not,  however,  be  over- 
looked that  hydrogen  destroys  three  times  as  much  oxygen 
as  is  destroyed  by  a  pound  of  carbon,  and  produces  but  little 
more  calorific  effect  per  pound  of  oxygen  consumed,  so  that 
it  is  equally  destructive  of  the  vital  properties  of  the  air  and 
introduces  an  excess  of  nitrogen  in  place  of  an  excess  of  carbon 
dioxide.  The  physiological  effect  of  the  carbon  dioxide  is  less 
to  be  feared  than  the  absence  of  oxygen  which  it  implies. 
Too  much,  therefore,  should  not  be  made  of  this  supposed 
advantage  of  liquid  fuel,  the  danger  being  due  to  the  absence  of 


Fig.  31.     MACALLAN  VARI- 
ABLE BLAST  CAP. 


APPLICATION  TO   STATIONARY  BOILERS      171 


oxygen.  The  Arlberg  tunnel  is  now  electrically  worked. 
No  very  large  installations  have  been  made  lately,  owing  to  the 
difficulty  in  obtaining  a  large  and  continuous  supply  of  oil  at  a 
price  low  enough  to  meet  the  competition  of  coal.  But  many 
heavy  locomotives  have  been  fitted  for  special  work  on  moun- 
tain sections  with  many  long  tunnels,  as  on  the  Italian  State 
Railways.  It  is  particularly  desirable  to  avoid  smoke  in 
tunnels. 

Locomotive  Boiler. 

Fig.  32  is  the  fire-box  used  for  liquid  fuel  on  the  Southern 
Pacific  Railroad,  the  oil  being  sprayed  into  the  front  of  the  fire- 
box below  the  mud  ring  and  under  the  usual  brick  arch  and 
directed  against  a  sloping  brick  lining  of  the  back  plate.  The 
sides  of  the  box  are 
cased  in  bricks,  and 
there  are  openings 
for  air  in  the  brick 
bottom  to  admit  air 
under  the  flame.  A 
central  brick  arch 
baffle  is  thrown 
across  the  middle 
of  the  fire-box,  and 
an  arch  is  thrown 
across  just  below 
the  fire-door.  The 

plates  of  the  upper  part  of  the  box  are  bare,  and  the  results 
are  said  to  be  satisfactory. 

According  to  Mr.  Holden  the  fuel  tank  should  be  above  the 
level  of  the  atomizers.  This  is  a  point  with  which  all  do  not 
agree  ;  some  consider  that  the  fuel  ought  to  be  pumped  to 
the  atomizers,  and  no  oil  should  be  able  to  flow  by  gravity 
with  the  attendant  risks  in  case  of  rupture. 

Unless  an  independent  source  of  steam  is  available,  steam 
should  be  raised  in  the  boiler  by  an  ordinary  fire  to  a  pressure 
of,  say,  25  pounds,  when  the  liquid  fuel  apparatus  may  be 
started. 

Oil  burners  must  not  be  started  before  there  is  a  flame  in  the 
furnace  ;  if  doubtful,  a  few  pieces  of  wood  or  some  oily  waste 
should  be  set  alight  in  the  furnace  before  applying  the  oil. 

The  above  rules  are  applicable  to  all  systems  of  oil  burning. 
A  common  danger  is  the  risk  of  gases  accumulating  in  the  fur- 
nace and  leading  to  explosion  when  the  dampers  are  opened 
and  flame  produced.  As  with  coal,  the  accumulation  of  gas 


Fig.  32.     LOCOMOTIVE  FiRE-Box  FOR  OIL  FUEL 
SOUTHERN  PACIFIC  EAILROAD. 


172         LIQUID  FUEL  AND  ITS  APPARATUS 

may  be  prevented  by  drilling  a  two-inch  hole  near  the  top  of  the 
damper,  so  that  when  the  damper  is  closed  there  is  always  a 
vent  through  it  which  will  stop  any  accumulation  of  gas. 

The  atomizing  agent,  whether  steam  or  air,  should  be  hot ; 
high  pressure  steam  is  better  than  low  pressure  steam  ;  the 
tendency  is  to  force  the  oil  forward  at  a  considerable  pressure 
to  the  burners  and  compel  it  to  escape,  by  a  fine  opening,  there- 
by probably  tending  to  atomize  itself  somewhat. 

The  practice  in  America  generally  is  towards  pumping  oil 
to  the  burners  rather  than  allowing  it  to  flow  by  gravity. 

Air  at  a  moderate  pressure  appears  to  be  as  competent  to 
atomize  oil  as  steam  at  a  high  pressure.  No  explanation  of 
this  is  given,  but  it  is  partially  due  to  the  greater  density  of  air 
and  probably  in  part  to  the  fact  that  air  is  a  supporter  of 
combustion  and  induces  earlier  combustion  or  ignition. 

The  Meyer  System. 

This  is  shown  in  Fig.  33,  and  is  a  modification  of  the  Korting 
system.  Oil  is  supplied  by  the  Korting  system  and  air  is  ad- 
mitted through  specially  placed  blades  in  an  extension  of  the 
furnace  front,  the  air  being  heated  in  a  surrounding  jacket, 
which  is  arranged  with  spiral  divisions.  The  air  is  delivered 
to  the  surface  in  a  whirling  manner,  and  the  system  has  been 
at  work  on  several  Dutch  steamers  with  success  and  similar 
general  types  of  apparatus  have  been  running  in  Roumania. 


THE  MIXED  SYSTEM  OF  COAL  AND  LIQUID  FUEL  COMBUSTION 

There  is  more  in  the  mixed  system  than  mere  convenience. 
The  simultaneous  use  of  solid  and  liquid  fuel  in  the  same  furnace 
modifies  the  conditions  for  each. 

For  coal  the  efficiency  of  combustion  is  better ;  for  oil  the 
heat  is  better  utilized. 

Combustion  on  the  grate  may  be  imperfect,  but  the  oil 
atomizer  so  mixes  up  the  gases  from  the  grate  with  the  air 
admitted  through  and  above  it,  that  combustion  is  much 
improved  and  the  excess  of  air  is  used  by  the  oil. 

Where  the  oil  is  only  a  fifth  of  the  coal,  the  coal  equivalents 
of  the  oil  appears  enormous. 

According  to  M.  Bertin,  where  5  kilos,  of  coal  would  ordinarily 
develop  each  7,800  calories,  they  will  produce  9,200  calories,  a 
gain  of  7,000  calories.  The  excess  of  air  supplied  with  the  5 
kilos,  of  coal  would  be  20  cubic  metres,  and  this  would  suffice 
for  the  added  kilogram  of  oil,  which  would  produce  11,000 


178 


174          LIQUID  FUEL  AND  ITS  APPARATUS 


calories  with  no  further  air  supply.  A  total  of  18,000  calories, 
compared  with  the  original  output  of  7,800  calories  per  kilo, 
of  coal,  makes  the  ratio  of  oil  to  coal  appear  2-31.  Obviously 
a  part  of  this  is  due  to  coal,  but  it  may  fairly  be  credited  to  the 
system. 

The  limit  of  perfect  use  of  air  is  found  when  the  oil  is  one- 
third  of  the  coal,  and  the  ordinary  four  cubic  metres  of  excess 
air  still  furnishes  the  theoretical  11  cubic  metres  for  the  oil : 
the  apparent  equivalence  of  coal  and  oil  becomes — 

1,400  x  3  +  11,000  _,  0_ 
7,800 

These  ratios  are  not  perhaps  secured  in  practice,  but  serve 
to  point  to  the  possible  advantages  of  the  mixed  system  and 
what  should  be  aimed  at. 

With  half  and  half  coal  and  oil  the  ratio  becomes  1-77, 
a  figure  that  has  been  approached  in  certain  experiments  at 
Indret.  Ratios  of  3  and  over,  what  have  been  claimed,  cannot, 
as  Mr.  Bertin  says,  be  justified  on  any  hypothesis.  Nor  is  the 
total  consumption  of  the  oxygen  supplied  at  all  closely  ap- 
proached in  general  practice. 

The  proportion  of  free  oxygen  to  carbonic  acid  is  an  indi- 
cation of  the  excess  of  air  admitted.  The  ratio  of  the  air  ad- 
mitted to  that  used  is — 


CQ2  +  Q 

C02 
C02  + 


-  =  1  +  j^r-  per  volume,  and 
0       20-8 


These  figures  neglect  the  hydrogen. 

With  coal  burned  at  the  rate  of  100  kilos,  per  metre  2  of  grate, 
if  the  oxygen  measures  8  per  cent.,  and  with  200  kilos.,  say 
5  per  cent.,  the  fire  is  too  thin  or  the  draught  too  great.  With 
1  or  2  per  cent,  of  carbonic  oxide  the  fire  is  too  thick  and  the 
draught  poor.  Both  oxygen  and  CO  present  together  indi- 
cate bad  furnace  arrangements. 

A  test  at  Indret  of  the  trial  boiler  of  the  Jeanne  d'Arc  with 
coal  alone  gave  the  following  results — 


Coal  per  hour 
per  metre  a  of 
grate. 

Percentage  in  volume. 

I*T& 

C02. 

CO. 

0. 

N. 

90k. 

11 

1 

6 

82 

1-54 

140 

11 

1 

5 

83 

1-45 

200 

13 

0-5 

4 

82-5 

1-30 

APPLICATION  TO  STATIONARY  BOILERS      175 


The  same  boiler  on  the  mixed  system  gave  the  results  below — 


Per  hour  per  metre8 
of  grate. 

Air 

Pressure. 

Percentage  of  Gas. 

'+W 

Carbon. 

Petroleum. 

C02. 

CO. 

0. 

N. 

^KU          \ 

37k. 

10  mm. 

10 

0 

8 

82 

1-80 

/OK.      < 

30 

10 

10 

0 

8 

82 

1-80 

37 

10 

10 

0 

8 

82 

1-80 

50 

20 

8-5 

0 

9-5 

82 

2-12 

66 

25 

8-5 

0 

9-5 

82 

2-12 

( 

35 

25 

11 

0 

7 

82 

1-64 

150        \ 

55 

30 

11 

0 

7 

82 

1-64 

I 

75 

40 

11 

0 

7 

82 

1-64 

With  oil  alone  Mr.  Orde  found  as  below — 


CO2. 

CO. 

0. 

N. 

'  +  <£ 

Test  No.  1 
Test  No.  2 

13-2 
12-6 

0 
0 

3-6 
4-0 

83-2 
834 

1-27 
1-3S 

Average 

12 

0 

3-8 

83-3 

1-285 

a  better  result,  after  all,  than  the  mixed  system  produced. 

In  calculating  the  apparent  effect  of  mixed  fuel,  M.  Bertin 
assumes  the  case  of  a  boiler  working  1  hour  and  a  weight  of  water 
—  a  per  kilo,  of  coal  ordinarily, 
b  =  the  water  evaporated  per  kilo,  of  mixed  fuel, 
x  =  the  evaporation  attributed  to  one  kilo,  of  oil, 
C  =  weight  of  coal  burned  per  metre  2  of  grate, 
j>  on  ,,         ,,         ,,         ,,        ,, 

The  vapour  produced  by  C  +  D  of  mixed  fuel,  assuming  a 
to  be  as  in  the  ordinary  coal  fired  boiler,  will  be  Ca  +  Do;. 

Then  per  kilo,  of  mixed  fuel  we  have 

Ca  +  Vx  (C  +  D)6-Ca      ,    ,  C  „ 

'C^D     =  &,  which  gives  x  =  -~-  =6  -f-jy(6-a), 

Whence,  if  R  is  the  ratio  of  oil  to  coal,  we  have 


a 


a 


Tests  in  the  Furieux  made  to  determine  R  gave  the  following 
results  — 


D 

x 

C 

a 

x 

R=_ 

0-00 

9-05 





0-45 

9-05 

11-34 

1-25 

0-64 

9-05 

14-2 

1-56 

176          LIQUID  FUEL  AND  ITS  APPARATUS 


The  figure  1-56  was  greater  than  the  figure  found  for  oil 
used  alone,  but  was  not  confirmed  by  tests  at  Cherbourg  of  a 
Godard  boiler  with  too  forced  a  draught  and  badly  arranged 
oil  sprays,  for  the  effect  b  of  the  mixed  fuel  was  even  inferior 
to  that  of  coal  alone,  which  shows  how  much  the  efficiency 
depends  on  arrangements. 

The  value  of  R  was  sought  at  Indret  by  Mr.  Brillie  in  a  series 
of  tests  extending  from  the  end  of  1896  to  early  in  1900,  in  view 
of  applying  mixed  firing  to  boilers  of  Du  Temple  Guyot  type. 

The  atomizers  had  air  induction  passages  as  in  the  Orde 
atomizer,  Fig.  15,  but  no  air  heating.  The  flames  kept  short 
and  the  heat  kept  well  in  the  furnace,  and  high  values  of  R 
were  reached,  as  1-6  for  a  rate  of  combustion  of  100  kilos,  of 
coal  and  50  kilos,  of  oil  per  metre  2  of  grate.1 

The  tests,  however,  were  too  short  for  exactitude. 

Other  tests  made  only  upon  engine  power  are,  however, 
available. 
Let  c  be  the  coal  per  horse  power  ordinarily. 

„  e        „         „         „         „         in  the  mixed  system. 


d 


»  oil  „ 


Then  d  takes  the  place  of  c  —  e  in  the  production  of  one 
horse  power  so  that 


T>  , 


c  —  e 


The  following  table  is  a  resume  of  Navy  tests  on  the  loco- 
motive type  of  boiler  or  torpedo  boat  No.  109  at  Cherbourg. 


1st  Series. 

2nd  Series. 

3rd 

Series. 

Air  pressure.     .      • 
Coal  alone    .... 

h. 
c. 

15mm. 
1,337k 

13mm. 
1,337k 

12mm. 
1,337k 

25mm. 
1,354k 

26mm. 
1,354k 

29mm. 
1,354k 

50mm. 
1,506k 

/  Coal         ") 

e. 

979 

914 

581 

713 

721 

652 

1,219 

Mixed    1  petroim<  ! 

d. 

379 

388 

494 

405 

474 

655 

434 

ys  em  (^otal       je+d 

1,358 

1,302 

1,075 

1,118 

1,195 

1,307 

1,653 

Equivalent  =R  =£5  1 

0,94 

1,09 

1,53 

1,58 

1,33 

1,07 

0,66 

The  interest  lies  in  the  falling  off  at  high  pressures,  the 
furnace  being  too  short  satisfactorily  to  burn  the  oil  at  such 
rapid  draught. 

Where  60  kilos,  of  oil  were  used  to  80  kilos,  of  coal  with  draught 
but  little  forced,  R  was  found  to  be  1  -5,  and  the  mixed  system 
took  the  place  of  forced  draught,  with  a  result  equal  to  the 
combustion  of  170  kilos,  of  coal  only,  a  result  thought  very 
encouraging.  Very  discordant  results  were  obtained  on  the 

1  Kilos,  per  metre2 -^  5=  pounds  per  square  foot  nearly. 


APPLICATION  TO  STATIONARY  BOILERS       177 

Milan,  the  Surcouf,  the  Pakin,  and  the  Forbin.  On  the  Milan 
especially  oil  proved  very  unsuitable  to  the  furnaces  of  the 
Belleville  boiler,  as  might  be  anticipated.  On  the  Surcouf, 
on  the  contrary,  the  result  of  mixed  fuel  was  to  reduce  total 
fuel  consumption  nearly  to  half  that  of  coal  alone. 

M.  Bertin  does  not  express  any  final  opinion  on  mixed  sys- 
tems, but  claims  that  where  employed  it  is  essential  to  success 
that  all  the  details  should  be  simple  so  as  to  avoid  the  danger  of 
error  on  the  part  of  a  little-trained  personnel,  such  as  the  open- 
ing or  closing  of  certain  valves,  always  in  their  power  to  do. 

Generally  little  information  is  public  on  liquid  fuel  in  any 
Navy.  Nobody  knows  why  a  secret  is  made  of  it,  for  the 
efficiency  attained  with  liquid  fuel  outside  naval  practice  is 
such  that  better  results  are  scarcely  likely  to  have  been  attained 
within  it. 


CHAPTER   XI 

RUSSIAN  AND   AMERICAN  LOCOMOTIVE   PRACTICE 

The  Baldwin  Co.'s  System. 

THE  Baldwin  Locomotive  Co.  consider  that,  while  opinions 
upon  atomizers  differ  as  to  central  jet  burners  such  as 
the  Urquhart,  the  relative  position  of  the  oil  supply  and  other 
details,  their  own  burner  (Fig.  34)  is  a  satisfactory  one,  and 
has  been  applied  to  many  locomotives  in  Russia  and  the 
United  States. 

It  is  rectangular  in  section,  with  two  longitudinal  passages, 
the  upper  one  for  oil,  the  lower  one  for  steam.  The  oil  is 
regulated  by  a  plug  cock  on  the  feed  pipes,  the  handle  of  which 
extends  to  the  cab  within  easy  reach  of  the  fireman. 

Steam  is  admitted  to  the  lower  part  of  the  burner  through  a 
pipe  so  connected  to  the  boiler  as  to  ensure  dry  steam.  The 
control  valve  is  in  the  cab  close  to  the  fireman's  seat.  A  free 
outlet  is  allowed  for  the  oil  at  the  nose  of  the  burner  ;  the 
steam  outlet,  however,  is  contracted  at  this  point  by  an  ad- 
justable plate  which  partially  closes  the  port,  and  gives  a  thin 
wide  aperture  for  the  exit  of  the  steam.  This  wire-draws  the 
steam  increasing  its  velocity  at  the  point  of  contact  with  the  oil. 
and  giving  a  better  atomization.  A  permanent  adjustment  of 
the  plate  is  made  for  each  burner  after  the  requirements  of 
service  are  ascertained.  The  moving  of  the  plate  is  not  then 
required  except  for  cleaning  purposes.  The  oil,  as  it  passes 
through  the  burner,  is  heated  by  the  steam  in  the  lower  portion, 
and  flows  freely  in  a  thin  layer  over  the  orifice.  It  is  there 
caught  by  the  jet  of  steam  and  completely  broken  up  and  ato- 
mized at  the  point  of  ignition,  and  carried  into  the  fire-box 
in  the  form  of  vapour,  where  it  is  thoroughly  mixed  with  air 
and  burns  freely. 

It  is  computed  that  one  inch  of  breadth  of  slit  will  serve  for 
100  square  inches  of  cylinder  area,  so  that  the  breadth  of  a 
burner  is  B  =  D  2  x  -007854.  As  only  one  burner  is  used, 

178 


AMERICAN   LOCOMOTIVE   PRACTICE          179 


Fig.  34.     ATOMIZER.     BALDWIN  LOCOMOTIVE  Co. 


American  fire-boxes  being  narrow,  it  is  apparently  the  case 
that  one  cylinder  is  intended  to  be  taken,  and  not  the  area  of 
both  cylinders.  D  =  diameter  of  cylinder. 

Large  oil-pipes  deliver  a  full  supply  as  far  as  the  regulating 
cock,  to  permit  of  fine  ,  , 

adjustment  of  which  its 
orifice  is  not  circular 
but  square,  with  the 
diagonals  as  in  Fig.  35. 
The  necessary  changes 
to  fit  an  engine  to  use 
liquid  fuel  are  shown  in 

Fig.  36.    The  atomizer  Fig  35     OlL  REGULATING  CocK. 

is   attached    below  the  BALDWIN  LOCOMOTIVE  Co* 

mud  ring,  and  the  spray 

is  directed  upwards  into  the  fire-box,  which  is  fitted  with  a 
brick  arch,  a  liner  of  fire-brick  and  a  base  filling  the  front 


180 


181 


182          LIQUID  FUEL  AND  ITS  APPARATUS 

half  of  where  the  grate  usually  is  placed.  A  small  hearth 
is  placed  to  catch  any  drip  from  the  burner,  and  from  the 
lower  corner  of  the  bridge  there  is  built,  to  protect  each  side 
sheet,  a  triangular  wall  of  bricks  extending  with  its  lower  point 
to  the  back  plate.  The  side  walls  form  the  sides  of  the  fire- 
brick combustion  chamber.  The  "  ash-pan  "  is  retained  with 
its  air  dampers  to  admit  air  below  the  fires,  and  the  dampers 
should  shut  tight.  The  inner  side  of  the  fire-door  is  lined  with 
a  plate  of  fire-brick. 

The  latest  form  of  fire-box  (1911)  is  that  of  Fig.  37.  This  differs 
but  little  from  that  of  Fig.  36,  which  represents  a  coal  fire-box. 
The  arch  is  kept  low  and  the  upper  space  of  the  box  is  large. 
It  is  recommended  not  to  leave  too  little  space  between  the 
arch  and  the  crown  sheet ;  otherwise  the  flames  will  be  too 
severe  upon  the  crown  sheet  and  generate  too  severe  a  local 
heat.  The  ashpan  is  of  modified  form  as  shown.  The  weight 
and  volume  of  oil  for  a  given  mileage  will  be  about  half  that 
necessary  for  coal. 

A  report  of  the  Committee  of  the  American  Railway  Master 
Mechanics'  Association  says — 

Fuel  oil  can  be  used  in  almost  any  form  of  fire-box,  the  best 
place  for  the  burner  being  just  below  the  mud  ring,  spraying 
upward  into  the  fire-box.  In  some  recent  experiments  with 
oil  of  84°  gravity,  140°F.  flash,  and  190°F.  fire  test,  in  which 
the  boiler  had  27  square  feet  grate  area  and  2,135  square  feet 
of  heating  surface,  8  per  cent,  being  in  the  fire-box,  it  was  found 
that  there  were  about  39  pounds  of  oil  burned  per  square  foot 
of  grate  area,  about  0-45  pounds  per  square  foot  of  heating 
surface  per  hour,  the  equivalent  evaporation  from  and  at  212° 
being  about  12  J  pounds  of  water  per  pound  of  oil.  It  was  also 
computed  that  there  should  be  about  one-third  of  an  inch 
width  of  burner  for  each  cubic  foot  of  cylinder  volume. 

Or  volumes  of  both  cylinders  in  cubic  feet  -f-  3  —  width  of 
burner  in  inches  for  ordinary  locomotives.  For  compound 
engines  the  amount  of  steam  is  10  per  cent,  and  of  fuel  20  per 
cent,  less,  and  in  the  foregoing  formula  only  the  h.p.  cylinder 
volume  ought  to  be  considered. 

For  compound  locomotives  a  guide  to  an  approximate  idea 
of  the  value  of  oil  fuel  as  compared  with  coal  is  as  follows  : — 

Cost  of  coal  per  ton  (of  2,000  Ib.)  +cost  of  handling  (say  50  cents) 

X  10-7  X  7 

2,000  x  evaporative  power  of  coal 

=  Price  per  American  gallon  at  which  oil  will  be  the  equivalent 
of  coal.  To  find  the  price  per  English  gallon  multiply  by  1  -2. 


AMERICAN   LOCOMOTIVE   PRACTICE 


183 


In  these  computations  the  cost  of  both  oil  and  coal  is  con- 
sidered at  the  engine,  and  not  at  the  place  of  purchase. 

The  weight  and  volume  of  crude  petroleum  based  on  a 
specific  gravity  of  0-91,  which  is  about  the  average  of  the  Texas 
oil,  as  well  as  that  received  from  South  America,  is  given  below. 


WEIGHT   AND    VOLUME    OF    CRUDE   PETROLEUM. 


Pound. 

U.S.  Liquid  Gal. 

Barrel. 

Gross  Ton. 

Imp.  Gal. 

1 

•13158 

•0031328 

•0004464 

•1096 

7-6 

1-00 

•02381 

•003393 

•83 

319-2 

42-00 

1-00 

•1425 

35-00 

2,240-0 

294-720 

7-017 

1-00 

245-60 

For  convenience  in  obtaining  the  correct  approximate  weight  of 
oil,  the  gravity  conversion  table,  No.  XIV,  may  be  useful. 

In  American  practice  where  railroads  are  so  dirty  with  ash 
and  cinders  thrown  from  the  locomotives  by  the  powerful  blast 
employed,  oil  should  give  an  advantage  to  any  line  adopting  it 
that  cannot  be  so  securely  counted  on  in  Great  Britain,  where 
a,sh  throwing  is  less  prevalent. 

Oil  puts  a  stop  to  the  choking  of  the  tubes  of  the  boiler  and 
permits  tubes  to  be  employed  smaller  than  now  admissible  on 
account  of  liability  to  choke. 

Tubes  of  one  inch  diameter  might  be  used  if  enough  could 
be  got  in  to  give  the  requisite  area. 

The  economy  of  oil  is  not  merely  a  question  of  fuel  economy. 

Table  No.  XI  gives  the  economy  of  oil  at  its  relative  value 
compared  with  coal  on  both  the  fuel  account  and  all  ascertained 
economies,  the  second  value  being  based  on  1  pound  of  oil 
being  worth  2  of  coal  in  place  of  If,  as  on  the  mere  fuel  account. 
The  extra  economies  include  repairs  on  locomotives  and  ash 
handling. 

Dr.  Dudley's  formula  for  relative  price  is — 

P  —  price  of  oil  per  barrel. 
W=  weight  per  gallon  in  pounds. 
2,000  X  P     _  r  .      ,         N  =  gallons  per  barrel. 
W  X  N  X  R  R  =  ratio  of  oil  to  coal  =  If  or  2, 

according  to  conditions. 
C  —  price  of  coal  per  ton  of  2,000. 

For  tons  of  2,240  Ib.  use  this  number  in  the  numerator  in 
place  of  2,000.  The  weight  W  multiplied  by  N  will  be  the  same 
in  either  American  or  English  gallons,  and  the  barrel  is  always 
the  same,  so  that  only  the  pounds  per  ton  need  be  changed, 


184          LIQUID  FUEL  AND  ITS  APPARATUS 

the  price  of  coal  and  oil  of  course  being  given  in  the  same 
equivalents,  either  dollars  or  shillings. 

W  x  N  x  R  x  C 

~  2,000  (or  2,240  for  long  tons). 

The  Baldwin  Co.  do  not  recommend  crude  oil :  it  is  more  dan- 
gerous ;  it  has  an  exceedingly  unpleasant  odour,  and  it  is  not 
so  economical.  Crude  oil  contains  more  or  less  volatile  matter 
which  vaporizes  quite  readily.  With  the  necessary  use  of 
lanterns  and  open  lights  round  about  locomotives,  there  would 
be  more  or  less  danger  of  explosions.  In  the  case  of  a  wreck, 
if  the  oil  tank  was  ruptured,  it  would  be  almost  impossible  to 
prevent  a  fire.  As  to  the  odour  of  the  crude  oil,  it  would  cer- 
tainly be  extremely  unpleasant  to  ride  behind  a  locomotive 
fed  with  Lima  crude  oil.  Crude  oil  is  not  so  economical  as 
reduced  oil,  because  oil  is  sold  by  volume,  and  a  gallon  of  crude, 
instead  of  weighing  7-3  pounds,  weighs  from  say  6-25  to  6-5 
pounds,  and,  as  the  heat  is  proportionate  to  the  weight,  a  barrel 
of  crude  will  not  give  so  much  heat  as  a  barrel  of  reduced  oil. 
The  oil  used  on  the  Grazi-Tsaritzin  Railway,  and  believed 
to  be  quite  safe  to  use,  is  an  oil  not  below  300°F.  fire-test. 
Crude  oil  can  be  used  on  stationary  boilers,  where  it  is  kept  in 
tanks  and  brought  to  the  boilers  in  pipes. 

The  arguments  appear  sound,  in  view  of  the  disastrous  Ameri- 
can experiences  of  burning  railway  wrecks,  and  the  English 
experience  at  Abergele  ;  but  all  crude  oils  are  not  so  unpleasant 
as  the  Lima  oil  referred  to,  and  the  odour  should  not  live 
through  the  furnace.  Still  the  fire  risk  of  crude  oil,  with  its 
volatile  constituents  left  in,  is  to  be  avoided. 

In  experiments  on  the  Pennsylvania  Railroad,  it  was  found 
with  oil  at  30  cents  per  barrel,  that  it  cost  nearly  50  per  cent, 
more  to  take  the  same  train  of  cars  100  miles  by  means  of  oil 
than  by  means  of  coal. 

The  Urquhart  System. 

To  the  late  Thomas  Urquhart,  of  Dalny,  Scotland,  the  former 
Locomotive  Engineer  of  the  Grazi-Tsaritzin  Railway  of  Russia, 
is  due  the  first  notable  success  in  liquid  fuel  combustion.1 

Urquhart  brought  the  system  to  the  notice  of  engineers  in  a 
paper  read  at  Cardiff  in  1884. 

According  to  this  paper,  the  percentage  of  astatki  in  Russian 
oil  is  70  to  75  per  cent.,  while  Pennsylvania  oil  contains  but 
25  to  30  per  cent.,  the  two  products  being  the  complement  of 

1  Proceedings  of  the  Institute  of  Mechanical  Engineers,  1884. 


AMERICAN  LOCOMOTIVE  PRACTICE  185 

each  other.  This  fact  is  quite  consistent  with  approximately 
equal  proportions  of  carbon  and  hydrogen,  and  Table  XII 
is  given  to  illustrate  this.  The  following  is  an  abstract  of 
Urquhart's  paper — 

"  Comparing  naphtha  refuse  and  anthracite,  the  former  has  a 
theoretical  evaporative  power  of  16-2  pounds  of  water  per 
pound  of  fuel,  and  the  latter  of  12-2  pounds  at  a  pressure  of 
8  atm.  or  120  pounds  per  square  inch ;  hence  petroleum  has, 
weight  for  weight,  33  per  cent,  higher  evaporative  value  than 
anthracite.  In  locomotive  practice  a  mean  evaporation  of 
from  7  pounds  to  7J  pounds  of  water  per  pound  of  anthracite 
is  generally  obtained,  thus  giving  about  60  per  cent,  of  effi- 
ciency, while  40  per  cent,  of  the  heating  power  is  lost.  But 
with  petroleum  an  evaporation  of  12-25  pounds  is  practically 
obtained,  giving 

12  25 

—— —  =  75  per  cent,  efficiency. 

Thus  petroleum  is  theoretically  33  per  cent,  superior  to 
anthracite  in  evaporative  power  ;  and  its  useful  effect  is  25 
per  cent,  greater,  being  75  per  cent,  instead  of  60  per  cent. 
Weight  for  weight,  the  practical  evaporative  value  of  petroleum 
is  at  least  from 

12  25  -  7-50  12  25  -  7-00 

7>5Q  =63  per  cent,  to ^ =75  per  cent. 

higher  than  that  of  anthracite. 

Spray  Injector. 

"  Steam,  not  superheated,  being  the  most  convenient  for 
injecting  liquid  fuel  into  the  furnace,  it  remains  to  be  proved 
how  far  superheated  steam  or  compressed  air  is  superior  to 
saturated  steam — taken  from  the  highest  point  inside  the 
boiler,  by  a  special  internal  pipe.  In  using  several  systems 
of  spray  injectors,  he  invariably  noticed  the  impossibility 
of  preventing  leakage  of  tubes,  accumulation  and  inequality  of 
heating  of  the  fire-box. 

"  The  work  of  a  locomotive  is  very  different  from  that  of  a 
marine  or  stationary  boiler,  owing  to  the  frequent  changes  of 
gradient  on  the  line,  and  the  stoppages  at  stations,  which 
render  firing  with  petroleum  very  difficult ;  and  were  it  not  for 
properly  arranged  brickwork  inside  the  fire-box,  the  spray  jet 
alone  would  be  quite  inadequate.  The  efforts  of  engineers 
have  been  mainly  directed  towards  arriving  at  the  best  kind  of 
spray  injector  for  so  minutely  sub-dividing  a  jet  of  petroleum 


186          LIQUID  FUEL  AND  ITS  APPARATUS 

into  a  fine  spray,  by  the  aid  of  steam  or  compressed  air,  as 
to  render  it  easy  of  ignition.  For  this  object  nearly  all  the 
known  spray  injectors  have  very  long  and  narrow  passages  for 
petroleum  as  well  as  for  steam  ;  the  width  of  the  orifice  does 
not  exceed  from  J  mm.  to  2  mm.,  or  0-02  in.  to  0-08  in.,  and  in 
many  instances  is  capable  of  adjustment. 

"  With  such  narrow  orifices  any  small  solid  particles  which 
may  find  their  way  into  the  spray  injector  along  with  the  petro- 
leum will  foul  the  nozzle  and  check  the  fire.  Hence  in  many 
steamboats  on  the  Caspian  Sea,  although  a  single  spray  injector 
suffices  for  one  furnace,  two  are  used,  in  order  that  when  one 
gets  fouled  the  other  may  still  work  ;  but,  of  course,  the  fouled 
orifices  require  incessant  cleaning  out. 

"  Locomotives. — In  arranging  a  locomotive  for  burning  petro- 
leum, several  details  require  to  be  added  in  order  to  render  the 
application  convenient.  For  getting  up  steam,  to  begin  with, 
a  gas  pipe  of  1  in.  internal  diameter  is  fixed  along  the  outside 
of  the  boiler,  and  at  about  the  middle  of  its  length  it  is  fitted 
with  a  three-way  cock,  having  a  screw  nipple  and  cap.  The 
front  end  of  the  longitudinal  pipe  is  connected  to  the  blower 
in  the  chimney,  and  the  back  end  is  attached  to  the  spray 
injector.  Then  by  connecting  to  the  nipple  a  pipe  from  a 
shunting  locomotive  under  steam,  the  spray  jet  is  immediately 
started  by  the  borrowed  steam,  by  which  at  the  same  time  a 
draught  is  also  maintained  in  the  chimney.  In  a  fully  equipped 
engine-shed  the  steam  would  be  obtained  from  a  fixed  boiler 
conveniently  placed  and  specially  arranged  for  the  purpose. 
Steam  can  be  raised  from  cold  water  to  3  atm.  pressure  in 
twenty  minutes.  Auxiliary  steam  is  then  dispensed  with,  and 
the  spray  is  worked  by  steam  from  its  own  boiler  ;  a  pressure 
of  8  atm.  is  then  obtained  in  from  50  to  55  minutes  from  the 
time  the  spray  jet  was  first  started.  In  daily  practice,  when 
it  is  only  necessary  to  raise  steam  in  boilers  already  full  of  hot 
water,  the  full  pressure  of  7  to  8  atm.  is  obtained  in  twenty 
to  twenty-five  minutes.  While  experimenting  with  liquid 
fuel  for  locomotives,  a  separate  tank  was  placed  on  the  tender 
for  carrying  the  petroleum,  having  a  capacity  of  about  3  tons. 
But  a  separate  tank  on  'the  tender,  even  though  fixed  in  place, 
would  be  a  source  of  danger  from  the  possibility  of  its  moving 
forwards  in  case  of  collision.  As  soon  as  petroleum  firing  was 
permanently  introduced,  the  tank  for  fuel  was  placed  in  the 
coal  spaces  of  the  tender  between  the  two  side  compartments 
of  the  water  tank.  For  a  six-wheeled  locomotive  the  capacity 
of  the  tank  is  3J  tons  of  oil,  a  quantity  sufficient  for  250  miles, 


AMERICAN  LOCOMOTIVE  PRACTICE  187 

with  a  train  of  480  tons  gross,  exclusive  of  engine  and  tender. 
In  charging  the  tank  with  petroleum,  it  is  important  to  have 
strainers  of  wire  cloth  in  the  manhole  of  two  different  meshes, 
the  outer  one  having  openings  of,  say,  J  in.,  the  inner  say  of 
J  in.  [In  later  English  practice  the  strainer  is  much  finer  than 
this. — AUTHOR.]  These  strainers  are  occasionally  taken  out 
and  cleaned.  If  care  be  taken  to  prevent  solid  particles  from 
entering  with  the  petroleum,  no  fouling  of  the  spray  injector 
is  likely  to  occur,  and  if  an  obstruction  should  arise,  the  ob- 
stacle, being  of  small  size,  can  be  blown  through  by  screwing 
back  the  steam  cone  in  the  spray  injector  far  enough  to  let 
the  solid  particles  pass  and  be  blown  into  the  fire-box.  This 
expedient  is  easily  resorted  to  even  when  running  and  no  more 
inconvenience  arises  than  an  extra  puff  of  dense  smoke  for  a 
moment,  in  consequence  of  the  admission  of  too  much  fuel. 
Besides  the  two  strainers  in  the  manhole  of  the  petroleum 
tank  on  the  tender,  there  should  be  another  strainer  at  the 
outlet  valve  inside  the  tank,  having  a  mesh  of  J  in.  holes. 

"  In  lighting  up,  precise  rules  must  be  followed  to  prevent 
explosion  of  any  gas  accumulated  in  the  fire-box.  First  clear 
the  spray  nozzle  of  water  by  letting  a  small  quantity  of  steam 
brow  through,  with  the  ash-pan  doors  open  ;  at  the  same  time 
start  the  blower  in  the  chimney  for  a  few  seconds,  and  any  gas 
will  immediately  be  drawn  up  the  chimney.  Next,  place  on  the 
bottom  of  the  combustion  chamber  a  piece  of  cotton  waste 
or  shavings,  saturated  with  petroleum  and  burning  with  a 
flame.  Then  open  first  the  steam  valve  of  the  spray  injector, 
and  next  the  petroleum  valve  gently ;  the  first  spray  of  oil 
coming  on  the  flaming  waste  ignites  without  any  explosion 
whatever,  after  which  the  fuel  can  be  increased  at  pleasure. 
By  looking  at  the  top  of  the  chimney,  the  supply  of  petroleum 
can  be  regulated  by  observing  the  smoke.  The  general  rule  is  to 
allcw  a  light  blue  smoke  to  escape,  showing  that  neither  too  much 
air  is  being  admitted  nor  too  little.  The  combustion  is  under 
the  control  of  the  driver,  and  the  regulation  can  be  effected 
so  as  to  prevent  smoke  altogether.  While  running  the  driver 
and  fireman  should  act  together,  the  latter  having  at  his  side 
of  the  engine  the  four  handles  for  regulating  the  fire,  namely, 
the  steam  wheel  and  the  petroleum  wheel  for  the  injector, 
and  the  two  ash-pan  door  handles  in  which  are  notches  for 
regulating  the  air  admission.  Each  alteration  in  the  position 
of  the  reversing  lever  or  screw,  as  well  as  in  the  degree  of  open- 
ing of  the  steam  regulator  or  the  blast  pipe,  requires  a  corres- 
ponding alteration  of  the  fire.  Generally  the  driver  passes  the 
word  when  he  intends  shutting  off  steam,  so  that  the  alteration 


188          LIQUID  FUEL  AND  ITS  APPARATUS 


in  the  firing  can  be  effected  before  the  steam  is  actually  shut  off  ; 
and  in  this  way  the  regulation  of  the  fire  and  that  of  the  steam 
are  virtually  done  together.  This  care  is  necessary  to  prevent 
smoke  and  waste  of  fuel.  When,  for  instance,  a  train  arrives 
at  the  top  of  a  bank  which  it  has  to  go  down  with  the  brakes  on, 
exactly  at  the  moment  of  the  driver  shutting  off  steam  and 
shifting  the  reversing  lever  into  full  forward  gear  the  petro- 
leum and  the  steam  are  shut  off  from  the  spray  injector,  the 
ash-pan  doors  are  closed,  and  if  the  incline  be  a  long  one,  the 
revolving  iron  damper  over  the  chimney  top  is  moved  into 
position,  closing  the  chimney,  though  not  hermetically.  The 

accumulated  heat  is 
thereby  retained  in 
the  fire-box  ;  and  the 
steam  even  rises  in 
pressure,  from  the 
action  of  the  accumu- 
lated heat  alone.  As 
soon  as  the  train 
reaches  the  bottom 
of  the  incline  and 


steam  is  again  re- 
quired, the  first  thing 
done  is  to  uncover 
the  chimney  top ; 
then  the  steam  is 
turned  on  to  the 
spray  injector,  and 
next  a  small  quan- 
tity of  petroleum  is 
admitted,  but  with- 
out opening  the  ash- 
pan  doors,  a  small 
fire  being  rendered 
possible  by  the  entrance  of  air  around  the  injector,  as 
well  as  by  leakage  past  the  ash-pan  doors.  The  spray, 
immediately  on  coming  in  contact  with  the  hot  chamber, 
ignites  without  audible  explosion  ;  and  the  ash-pan  doors  are 
finally  opened,  when  considerable  power  is  required,  or  when 
the  air  otherwise  admitted  is  not  sufficient  to  support  complete 
combustion.  By  looking  at  the  fire  through  the  sight  hole, 
it  can  always  be  seen  at  night  whether  the  fire  is  white  or 
dusky  ;  in  fact,  with  altogether  inexperienced  men,  it  was 
found  that  after  a  few  trips  they  could  become  quite  expert  in 
firing  with  petroleum.  The  better  men  burn  less  fuel  than 


Fig.  38.    GOODS  LOCOMOTIVE,  URQUHART 
SYSTEM,  GBAZI-TSARITZIN  RAILWAY. 


AMERICAN  LOCOMOTIVE  PRACTICE  189 

others,  simply  by  greater  care  in  attending   to  the  essential 
points. 

"  Several  points  have  arisen  which  must  be  dealt  with  to 
ensure  success.  The  distance  ring  between  the  plates  around 
the  firing  door  is  apt  to  leak  hi  consequence  of  the  intense  heat 
and  the  absence  of  water  circulation  ;  it  is  therefore  protected 
by  having  the  brick  arch  built  up  against  it,  or,  better  still,  a 
flanged  joint  is  substituted.  This  arrangement  occasions  no 
trouble  whatever." 

The  fire-box  arrangement  of  the  goods  locomotive  is  shown 
in  Fig.  38.  The  sprayer  points  downwards  upon  the  hearth 
which  is  built  in  the  ash-pan,  and  continuous  with  the 
bridge  and  arch.  A  block  of  brickwork  is  placed  under 
the  sprayer,  and  below  that  is  a  passage  for  air.  The  bridge 
is  continued  up  to  the  crown  of  the  box,  but  is  perforated 
and  the  whole  of  the  front  tube  plate  is  exposed  to  heat.  The 
fire-box  surface  is  82  sq.  ft.  Total  heating  surface,  1,248  sq. 
ft.  "  Grate  "  area,  17  sq.  ft.  Weight,  36  tons  in  running 
order.  Pressure,  120  to  135  pounds.  151  tubes  13  ft.  10  in. 
long  X  2  in.  outside  diameter. 

Fig.  39  shows  the  petroleum  tank  in  the  tender,  the  heating 
coil  C  surrounding  the  filter  whence  the  oil  is  drawn  through  a 
cock  V  and  pipe  P  to  the  sprayer.  Steam  goes  by  way  of  the 
pipe  S  and  escapes  at  T.  W  is  the  collector  for  water. 

Fig.  40  shows  another  furnace  arrangement,  in  which  the 
brickwork  of  the  fire-box  sides  is  made  cellular,  and  air  is 
admitted  also  below  the  sides  by  lateral  openings  K  with 
regulating  dampers.  The  fire-doors  are  quite  blocked,  and  only 
a  sight  hole  left  at  H. 

A  later  design  is  that  of  Fig.  41.  This  includes  a  lined  ash- 
pan,  bridge  and  over-arch,  with  a  passage  through  it  for  air 
admitted  by  the  forward  ash-pan  damper.  Lateral  arches  are 
provided  in  order  that  the  side  sheets  of  the  fire-box  may  be 
exposed  to  the  heated  gases.  No  part  of  the  fire-box  is  actually 
in  touch  with  the  fire-brick,  yet  the  burning  oil  is  completely 
enclosed  with  a  brick  oven.  As  very  usual  in  Continental 
practice,  the  engines  had  the  closing  cap  to  the  chimney  top. 
This  is  used  to  retain  heat  in  the  fire-box  at  times  of  standing, 
and  should  be  a  most  effectual  damper.  With  liquid  fuel 
employed  without  solid  fuel,  the  closing  of  the  chimney  is  very 
efficient  in  retaining  the  heat  of  the  brickwork,  and  this  damper 
is  used  when  running  down  hill,  and,  on  again  turning  the  oil 
spray  into  the  furnace  it  is  at  once  ignited  by  the  hot  brickwork. 
There  is  a  pointer  and  scale  on  the  spindle  of  the  regulating 


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bfi 


190 


AMERICAN  LOCOMOTIVE  PRACTICE 


191 


valve  D  for  use  by  night.  The  Auther  has  noticed  on  the 
Great  Eastern  Railway,  that  when  apparently  quite  dark,  the 
chimney  top  can  be  seen  sufficiently  to  judge  of  smoke. 

The  injector  is  shown  in  Fig.  42.  It  consists  of  a  central 
steam  jet,  an  annular  passage  for  oil  and  an  outer  annulus 
for  air.  The  steam  jet  is  regulated  by  screwing  the  steam  cone 


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to  and  fro  by  a  worm  and  wheel  on  the  regulating  handle 
and  spindle.  The  steam  cone  can  readily  be  removed  for 
clearing  purposes,  or  the  back  plug  can  be  taken  out  while 
the  sprayer  is  at  work,  with  little  delay,  a  wire  being  intro- 
duced to  remove  any  possible  obstruction  that  the  steam  will 
not  discharge. 


193 


Sprct,y     Injector. 


OiJ^  ^Sm.    Longitudinal,    Sec&cm 


O         2 


Fig.  42.     ATOMIZER.     URQUHART'S. 

193 


194          LIQUID  FUEL  AND  ITS  APPARATUS 

Economies  of  45  and  57  per  cent,  over  anthracite  and  bitum- 
inous coal  changed  to  57  and  67  in  an  engine  arranged  to  warm 
the  air  slightly,  and  Urquhart  thought  the  air  ought  to  be 
heated,  and  this  is  well  established  as  good  practice. 

The  fuel  consumption  of  all  kinds  appears  high,  but  this  is 
attributable  to  long  waiting  on  a  single  line  and  to  the  weight 
of  trains,  often  as  much  as  720  tons,  and  the  exposed  country, 
with  strong  side  winds. 


Consumption    of 
Coal  -  fiul  lines 


Fuel  per   Train  -  Mile 
PeiroieTzrrL  :  -    Dotted    tines 


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C   Mjced  4-        .  ,  Minced        . 

DP  4  „  'Passenge*    . 

Fig.  43.     LOCOMOTIVE  PERFORMANCES  WITH  COAL  AND  OIL  FUEL. 
URQUHART'S  SYSTEM,  GRAZI-TSARITZIN  RAILWAY. 

Considerable  space  has  been  given  to  this  system  and  to  the 
figures  and  drawings,  because  though  now  old  and  dating  back 
nearly  30  years,  Urquhart  had  the  correct  principles  of  combus- 
tion fully  before  him,  and  laid  out  his  arrangements  with  a 
perfection  that  cannot  be  much  improved  upon  to-day.  He 
saw  clearly  what  was  necessary,  and  this  may  be  summed  up 
in  the  words,  Atomizing,  Air  and  Temperature.  Hence  the 
success  he  attained,  and  the  correctness  of  his  arrangements 
and  conclusions. 

In  Fig.  43  are  curves  showing  the  consumption  of  oil  and 
coal,  and  in  Table  XIII  are  some  useful  data  on  specific  gravity. 


CHAPTER   XII 

AMERICAN   STATIONARY  PRACTICE 

The  Billow  System. 

fuel  oil  appliances  of  the  National  Supply  Company  of 

.       Chicago  consist  of  pumps  and  atomizers. 

Atomizers  are  actuated  in  one  or  a  combination  of  the  follow- 
ing ways — by  steam,  by  air  supplied  by  an  air  compressor,  or 
from  a  positive  blast  blower  or  fan. 

An  oil  burner  becomes  more  efficient  and  approaches  nearer 
to  perfection  which  will  pulverize  the  greatest  amount  of  oil 
with  the  least  energy,  and  will  vaporize  oil  at  the  point  of 
expansion  of  the  agent  used  for  that  purpose. 

Atomizers  are  constructed  with  various  shaped  openings — 
annular,  flaring,  slotted,  semicircular  or  fan-shaped,  producing 
either  a  long,  round,  or  a  broad  spreading  flame. 

Annular  openings  are  said  to  be  more  economical  in  steam  or 
air  than  other  forms,  as  a  more  intimate  association  of  the  oil 
and  the  vaporizing  agent  is  afforded. 

By  actual  experiment  atomizers  consume  from  3  to  15  per 
cent,  of  the  entire  product  of  the  boiler  in  vaporizing  sufficient 
oil  to  develop  the  capacity  of  the  boiler. 

The  number  of  atomizers  required  for  each  boiler  or  furnace 
is  directly  proportionate  to  its  size.  Of  atomizing  agents  steam 
is  considered  the  best  for  boilers,  air  from  a  positive  blast 
blower  for  furnaces  where  heat  of  medium  intensity  is  required, 
and  air  from  a  compressor  for  small  furnaces.  These  are 
opinions  not  held  universally  as  regards  boiler  furnaces. 

The  Billow  Atomizer  (Fig.  44)  is  designed  to  vaporize  the 
greatest  amount  of  oil  with  the  least  expenditure  of  energy, 
is  automatic  in  its  operation  within  a  5  per  cent,  steam  variation. 
It  is  of  a  form  which  it  is  claimed  precludes  the  possibility  of 
choking,  clogging,  dripping  or  the  wasteful  use  of  steam,  air  or 
oil.  It  is  self  contained.  The  fuel  and  the  atomizing  agent 
are  controlled  within  the  burner.  It  has  ground  joint  union 
pipe  connexions  placed  on  an  axis  transverse  to  the  body,  a 

195 


196 


LIQUID  FUEL  AND  ITS  APPARATUS 


feature  which  permits  the  flame  to  be  directed  as  desired.  It 
has  a  wide  range  in  adjustment,  and  will  vaporize  a  few  drops 
of  oil  per  minute  or  many  gallons  per  hour.  It  is  constructed 
with  various  shaped  nozzles  or  outlets  of  the  retort  type, 
when  desired,  but  these  are  not  recommended  on  account  of 
their  wasteful  steam  or  air  consumption.  Only  in  special 


Scale 


Fig.  44.     ATOMIZER.     BILLOW  SYSTEM. 

instances  should  atomizers   other  than  those  with  annular 
openings  be  employed. 

Fuel  Oil  Pumping  Systems. 

In  America  oil  is  pumped  to  the  atomizer,  not  gravitated. 
The  system  for  oil  handling  and  control  between  the  storage 


AMERICAN  STATIONARY  PRACTICE  197 

tank  and  the  atomizers  is  an  important  factor.  This  system 
is  designed  to  -heat  the  oil,  free  it  from  mechanical  impurities, 
and  deliver  it  to  the  atomizer  at  a  constant  pressure  and 
temperature  under  the  control  of  the  operator.  The  amount  of 
oil  necessary  for  feeding  the  atomizers  should  be  automatically 
controlled,  and  the  system  sufficiently  flexible  to  pump  the 
oil  to  one  atomizer  or  any  number  within  its  capacity  without 
useless  expenditure.  It  should  handle  all  grades  of  oil  fuel 
equally  well. 

Residuum,  or  manufactured  fuel  oil,  often  contains  particles 
of  coke  and  sand.  All  grades  may  have  dirt  and  other  matter 
which  disturb  the  adjustment  of  the  atomizers  at  the  furnace 
door,  necessitating  their  frequent  cleansing.  These  impurities 
clog  the  feed  lines,  necessitating  frequent  blowing-out.  An 
oil  pumping  system  provides  against  this  by  filtering  out  these 
accumulations  and  cleaning  the  filtering  medium  without 
disturbing  the  continued  performance  of  the  pump. 

Feeding  the  oil  at  a  temperature  nearly  approaching  the 
point  of  distillation  ensures  speedy  vaporization,  with  a  result- 
ant flame  soft  and  diffusing,  and  not  sharply  impinging  upon 
the  boiler  surfaces.  The  pumping  "system  is  designed  to 
give  the  desired  heat,  and  is  provided  with  automatic  govern- 
ing valves  to  ensure  uniform  delivery. 

The  National  Supply  Co.  have  designed  oil  fuel  pumping 
systems  for  modern  fuel  oil  non-gravity  equipments.  They 
are  compact,  and  so  dripped  and  drained  that  no  oil  can  reach 
the  floor. 

Any  oil  fuel  produces  the  best  results  when  heated  to  a  tem- 
perature just  under  its  distilling  point,  and  oil  is  atomized 
with  less  energy  when  heated  to  such  a  temperature  and 
delivered  under  constant  pressure. 

When  air  is  used  as  an  atomizing  agent,  carbonization  is  not 
liable  to  occur  at  the  outlet  of  the  burner  in  the  furnace  because 
the  oil  is  passed  through  water  heated  with  exhaust  steam  in 
the  receiver,  and  minute  quantities  of  water  vapour  are  carried 
over  with  the  oil  and  prevent  carbonizing. 

Double  Pumping  System. 

These  oil  pumping  systems  (Fig.  45)  consist  generally  of  two 
duplex  steam  pumps,  specially  brass  fitted  for  oil,  and  of  a 
cast-iron  receiver,  tested  to  two  hundred  pounds  pressure, 
mounted  on  a  cast-iron  drip  pan  and  base  frame  upon  which  the 
mechanism  is  fastened.  A  partition  divides  the  receiver  into 
two  chambers.  Projecting  into  the  rear  chamber  and  screwed 


198         LIQUID  FUEL  AND  ITS  APPARATUS 

to  the  partition  are  tubes  with  fine  gauze  heads,  accessible 
through  the  rear  head  of  the  receiver.  These  heads  act  as  a 
straining  medium,  and  there  is  a  blow-off  pipe  and  valve  for 
removing  deposit. 


Fig.  45.     DOUBLE  PUMPING  SYSTEM.     CAPACITY,  1  to  5,000  BOILER  H.P. 

The  forward  chamber  is  usually  two-thirds  full  of  water, 
and  contains  a  coil  of  pipe  through  which  flows  live  steam  or 
exhaust  steam  from  the  pump.  The  coil  has  controlling  valves, 
permitting  the  use  of  steam  from  either  of  these  sources  or  both 
at  the  same  time. 


AMERICAN   STATIONARY  PRACTICE 


199 


One  pump  is  in  reserve  against  contingencies  or  accident  to 
the  other. 

The  apparatus  is  provided  with  a  pump  governor,  or  regu- 
lator, actuated  by  the  pressure  in  the  receiver  to  maintain  a 
constant  pressure  on  the  oil  in  the  receiver  ;  an  adjustable  relief 
valve  placed  between  the  suction  and  the  delivery  side  of  the 
pump  through  which  all  oil  in  excess  of  the  requirements  of  the 


Fig.  46.     COMPOUND  TUYERE  FOR  AIR  ADMISSION. 

atomizer  may  pass  in  case  of  accident  to  the  governor  ;  a 
thermometer,  steam,  oil,  pressure,  and  automatically  closing 
sight  gauge. 

The  oil  is  discharged  through  the  force  chamber  of  the  pump 
into  the  forward  chamber.  The  oil  flowing  through  the  hot 
water  becomes  heated  and  passes  out  through  an  inner  tube 
to  the  point  of  consumption. 

These  pumping  systems  are  made  up  to  sizes  of  ten  to 
eighteen  thousand  boiler  horse-power. 


200         LIQUID  FUEL  AND  ITS  APPARATUS 


Thus  No.  5  Double,  employing  two  5j-in.  by  3J-in.  by  5-in. 
duplex  steam  pumps,  has  a  capacity  of  five  to  fifteen  thousand 
boiler  horse-power,  or  twenty  to  forty  gallons  per  minute. 

In  attaching  fuel  oil  atomizers  to  furnace  or  boiler  fronts  it 
is  sometimes  necessary  to  admit  all  the  air  for  vaporization 

and  combustion  at 
the  atomizer,  for  the 
reason  that  at  no 
other  point  can  a 
sufficient  amount  of 
air  be  induced  into 
the  furnace  to  com- 
plete combust  ion, 
owing  to  conditions  of 
draught  or  construc- 
tion. The  device  of 
Fig.  46  answers  this 
purpose,  by  providing 
the  air  for  combustion 
irrespective  of  the 
atomizing  agent  used. 
This  air  for  combus- 
tion is  intimately 
mixed  with  the  oil  at 
the  point  of  admission 
into  the  furnace.  It 
is  intended  for  boilers 
where  oil  is  burned 
as  an  auxiliary  to 
some  other  form  of 
fuel,  making  it  im- 
possible to  dispense 
with  the  grate  bars, 
and  is  therefore  use- 
ful in  connexion  with 
the  burning  of 
bagasse,  sawdust  and 
material  of  like  char- 
acter. It  is  also  the 
form  used  aboard 
vessels  that  employ 
water  tube  boilers. 
The  tuyere  or  air  regulator  attached  is  shown  enlarged  in 
Fig.  47,  the  outer  part  being  revolvable  so  as  to  close  the  air  slots 
and  regulate  the  air  admitted  round  the  atomizer.  These 


Fig.  47.     AIR  REGULATOR,  ATOMIZER  AND 
TUYERE  BLOCK  FOR  FURNACE  FRONT. 


AMERICAN  STATIONARY  PRACTICE 


201 


appliances  are  the  designs  of  the  National  Supply  Co.,  of 
Chicago,  as  also  is  the  arrangement,  Fig.  49,  of  atomizer 
tuyere,  casting,  and  internal  block  of  fire-brick  which  is 
intended  to  be  placed  in  a  furnace  wall  or  in  the  fire- front  of 
a  boiler.  The  fire-brick  has  a  trumpet-shaped  hole  through 
it,  and  the  nozzle  of  the  atomizer  enters  a  short  distance 
only,  so  that  the  initial  flame  is  contained  within  the  body 
of  the  block.  This  block  has  a  good  effect  in  effecting  perfect 
combustion. 

An  example  of  the  National  Co.'s system  is  the  fuel  oilplant 
of  the  Union  Loop,  Chicago,  Illinois.  This  plant  consists  of  a 
system  for  the  unloading,  storing,  circulating,  controlling 
and  firing  of  fuel  oil,  after  designs  prepared  by  C.  0.  and  E.  E. 
Billow. 


(J 

i 

i 
; 

Fig.  48.     SPECIAL  TANK  CAB  S-INCH  HOSE  CONNEXION. 

The  plant  includes  three  steel  storage  tanks,  16,  10,  and  8 
feet  in  diameter,  and  20  feet  high,  of  a  combined  capacity 
of  1,764  bbls.,  of  42  U.S.  gallons  each  (35  imp.  gals.). 

Fuel  oil  is  received  in  tank  wagons,  and  transferred  to  the 
tanks  by  two  duplex  pumps,  having  6-in.  steam  and  7|-in.  oil 
cylinders,  and  a  6-in.  stroke.  These  pumps  have  6-in.  suction 
and  5-in.  discharge. 

Provision  is  made  for  unloading  four  30  bbl.  tank  wagons 
simultaneously.  These  tank  wagons  are  attached  to  oil 
hydrants,  by  steel  band  lined  oil  unloading  hose. 

The  storage  tanks  are  provided  with  flanges  for  pipe  con- 
nexions, a  16-in.  screw  top  manhole  and  cover  on  the  roof,  and 
an  18-in.  on  the  side  near  the  bottom  of  the  tank,  floats  and 
level  indicators  by  finger  boards  in  the  tank  room  and  mercury 
columns  in  the  basement. 

From  the  storage,  the  oil  is  conveyed  to  two  4-in.  stand  pipes, 
70  ft.  in  height,  joined  by  a  header  near  the  top,  by  means  of  a 


202         LIQUID  FUEL  AND  ITS   APPARATUS 

duplex  pump,  having  3|-in.  steam  cylinder,  4f-in.  oil  cylinder, 
and  a  5-in.  stroke.  This  pump  has  a  3-in.  suction  and  a  21- 
inch  discharge. 

From  the  stand  pipe  header  the  oil  is  conveyed  to  the  oil 
atomizer  loop,  by  two  No.  5  oil  heating  and  circulating  systems, 
set  upon  the  boiler  room  floor.  These  automatically  maintain 
a  uniform  pressure  and  temperature,  and  a  constant  flow  of  oil. 
They  consist  of  a  battery  of  duplex  pumps  with  5j-in.  packed 
pistons  having  3|-in.  oil  cylinders,  a  5-in.  stroke,  a  2|-in. 
suction  and  a  2-in.  discharge.  Each  pump  has  a  copper  air 


Fig.  49. 


chamber  and  is  mounted  on  a  cast-iron  base  and  drip  pan,  to 
dispose  of  all  leakage  of  glands.  The  base  is  attached  to  a 
cast-iron  frame,  supporting  one  combined  steel  receiver,  heater 
and  condenser,  24  inches  in  diameter,  and  36  inches  high,  sur- 
mounted by  the  7-in.  copper  air  chamber  24  inches  high.  The 
receiver  has  two  diaphragms  riveted  to  its  shell,  and  expanded 
full  of  tubes  (125  1-in.  boiler  tubes,  having  their  ends  caulked 
and  beaded),  around  which  passes  the  exhaust  from  the  pumps. 
The  receiver  also  has  provision  for  the  introduction  of  water, 
through  which  the  fuel  oil  flows,  under  a  high  pressure,  for  the 
purpose  of  breaking  it  up,  in  order  that  all  foreign  substances 
may  be  precipitated  ;  the  oil  passing  through  the  heated  tubes 
is  thoroughly  cleansed,  and  deposits  water  and  settlings. 


AMERICAN    STATIONARY    PRACTICE  203 

The  drips  from  the  pumps  receiver,  drip  pans,  and  exhaust 
have  catch  basin  connexions. 

The  whole  system  is  as  nearly  automatic  in  its  action  as  is 
desirable,  and  is  duplicate  throughout. 

Each  system  is  capable  of  delivering  sufficient  fuel  oil  to 
develop  15,000  horse-power,  and  occupies  a  floor  space  of  30 
sq.  ft.,  and  is  8  ft.  in  height. 

Four  atomizers  are  placed  in  the  combustion  chamber  of 
each  boiler,  or  a  total  of  sixty-four  oil  burners  compose  the 
installation.  These  oil  burners  receive  their  oil  from  a  loop, 
beneath  the  boiler  room  floor,  which  is  divided  by  valves  into 
five  distinct  headers. 

The  furnaces  are  erected  upon  the  grate  bars  of  an  Acme 
stoker,  and  consist  of  a  series  of  fire-brick  flues  for  heating 
and  circulating  the  incoming  air,  chequer  work  for  distributing 
flame,  and  baffle  walls  for  directing  same. 

Oil  at  the  same  uniform  pressure  and  temperature  can  be 
delivered  to  a  single  burner  or  to  the  entire  sixty-four. 

Furnace  Construction. 

"  Too  often  it  happens  that  complete  combustion  is  impaired 
not  from  the  lack  of  air,  but  on  account  of  the  method  of  its 
introduction  into  the  furnace,  often  from  such  points  as  to 
render  it  ineffective,  producing  losses  as  great  as  50  per  cent. 
For  economic  reasons  no  more  air  should  be  supplied  than  is 
necessary. 

"During  the  early  stages  of  combustion  of  any  fuel  the  gases 
of  a  highly  volatile  nature  distil  at  a  low  temperature,  rise 
rapidly,  hug  the  boiler,  enter  the  tubes  or  flues  and  pass  away 
unconsumed.  The  combustion  chamber  should  therefore  be 
arranged  with  fire-brick,  so  that  the  incoming  air  may  be  heated 
to  the  required  temperature,  the  flames  retarded,  diffused, 
and  distributed,  and  the  velocity  impeded.  There  will  be  no 
concentration  or  localization,  and  the  danger  of  blistering  or 
burning  is  avoided. 

"The  furnace  construction  varies  according  to  the  type  of 
boiler  or  furnace.  The  question  may  be  asked,  *  Will  an 
apparatus  work  if  no  change  is  made  in  the  combustion  chamber 
or  furnace  of  a  boiler  other  than  that  of  covering  the  grate 
bars  ?  '  A  furnace  so  arranged  will  not  average  so  high 
economical  results  as  when  constructed  for  diffusing  the  heat 
and  retarding  the  flow  of  the  gases.  Fuel  oil  appliances  can 
only  vaporize  the  oil ;  in  the  furnace  it  is  consumed.  There- 
fore the  statement  is  not  unreasonable  that  a  scientifically 


204          LIQUID  FUEL  AND  ITS   APPARATUS 

arranged  combustion  chamber  with  a  shovel  to  feed  the  oil  is 
preferable  to  a  poorly  constructed  furnace  to  which  is  attached 
the  highest  type  of  atomizing  device. 

Operating  a  Fuel  Oil  Plant. 

"  The  results  to  be  secured  from  a  properly  designed  fuel  oil 
plant  depend  largely  upon  the  amount  of  intelligence  exercised 
in  its  manipulation.  All  the  mechanism  that  can  be  supplied, 
outside  of  the  furnace,  is  designed  to  perform  the  single  function 
of  delivering  the  oil  to  the  furnace  in  a  finely  divided,  nebulized 
condition  with  as  little  cost  to  the  operator  as  possible,  and  to 
give  insurance  against  accidents  or  possible  shut-downs,  with 
ease  and  facility  in  manipulation.  Other  economical  results 
depend  wholly  upon  the  draught.  This  should  be  regulated  by 
the  ash-pit  doors,  or  other  proper  means.  The  flame  may  be 
increased  or  diminished  at  will  by  the  simple  opening  or  closing 
of  a  valve,  but  it  is  only  by  experiment  or  long-continued  con- 
tact with  fuel  oil  that  the  oil,  the  atomizing  agent,  and  the  air 
necessary  for  combustion  will  be  properly  combined  and  the 
beneficial  results  of  this  combination  be  obtained.  The  operator 
should  continue  the  opening  and  closing  of  the  ash-pit  doors, 
or  the  manipulation  of  the  damper  and  the  increasing  or 
diminishing  of  the  flame  until  he  can  produce  a  fire  large  or 
small,  without  the  least  indication  of  smoke.  When  this  con- 
dition is  attained  he  will  have  no  more  occasion  for  handling  any 
of  the  apparatus  provided  the  elements  of  combustion  are 
perfectly  balanced. 

"  The  gases  should  not  pass  from  the  furnace  at  two  high  a 
temperature.  This  can  be  controlled  and  regulated  largely 
by  the  damper.  A  clear  flame  consumes  less  oil  than  a  smoky 
flame,  and  has  greater  efficiency.  Smoke  is  evidence  of  imper- 
fect combustion,  but  the  absence  of  smoke  does  not  necessarily 
prove  that  perfect  combustion  is  being  attained.  Too  much 
steam  produces  a  light  grey  vapour  ;  too  little,  a  smoky  flame  ; 
too  great  a  draught,  an  intensely  vibrating  flame  accompanied 
with  a  roaring  noise  ;  too  little  draught  produces  a  dull  red 
smoky  flame.  When  the  elements  are  properly  united  the 
result  is  a  reddish  orange  flame. 

"  The  temperature  of  the  escaping  gases  from  a  boiler  will 
increase  as  the  excess  of  air  becomes  greater,  provided  the  same 
amount  of  fuel  is  being  burned.  This  is  because  the  furnace 
temperature  is  less,  owing  to  the  greater  amount  of  air  present 
which  results  in  a  less  rapid  transfer  of  the  heat  to  the  boiler 
and  consequently  allows  more  heat  to  escape  to  the  chimney. 


206 


206         LIQUID  FUEL  AND  ITS  APPARATUS 

"  On  the  other  hand,  with  a  uniform  excess  of  air,  if  more  fuel 
is  burned,  the  temperature  of  the  escaping  gases  will  increase, 
owing  to  the  heat  produced  being  greater  in  proportion  to  the 
absorbing  capacity  of  the  boiler." 

It  is  only  through  close  application  that  the  theory  of  oil 
burning  can  be  fully  understood  and  mastered  and  as  high  an 
efficiency  as  80  per  cent,  of  the  theoretical  value  of  the  fuel 
transmitted  from  the  furnace  to  the  boiler.  Mr.  C.  0.  Billow 
has  designed  furnaces  for  many  types  of  boilers.  Fig.  50  is  the 
ordinary  American  under-fired  tubular  boiler  with  the  bars 
replaced  by  a  fire-brick  air  casing,  through  which  air  flows  to 


Fig.  51.     WATER-TUBE  BOILER.     BILLOW  SYSTEM. 

the  furnace  through  the  "  ash-pit  "  door  and  comes  up  under 
the  atomized  jet.  The  furnace  widens  out  laterally  from 
front  to  rear,  the  atomizer  being  placed  at  the  narrow  end  of 
this  brick  furnace.  The  grate  bars  are  ten  inches  lower  than 
usual,  and  the  air  casing  of  brick  occupies  this  ten-inch  space. 
The  ash-pit  doors  regulate  the  air  admission.  The  atomized 
oil  is  directed  upon  the  chequer  work  brick  bridge,  which 
breaks  up  and  diffuses  the  flame  throughout  the  furnace  and 
directs  it  upon  the  boiler.  A  hanging  bridge  is  placed  at  the 
extreme  end  of  the  combustion  chamber.  If  too  little  air  has 
been  admitted  at  the  front,  a  further  supply  is  let  in  through 
this  rear  bridge,  which  also  serves  further  to  retard  the  flow 


AMERICAN  STATIONARY  PRACTICE 


207 


of  the  hot  gases.  Either  steam  or  air  may  be  used  as  the 
atomizing  agent,  and  though  air  is  the  more  efficient,  the  cost 
of  the  air  compressor  detracts  from  its  advantage,  but  a  good 
compressor  saves  steam.  Mr.  Billow  considers  that  steam 
atomizing  should  be  done  with  3-3  per  cent,  of  the  total  steam ; 
that  a  positive  air  blast  blower  will  only  use  1-36  per  cent,  of  the 
boiler  output,  but  when  air  is  compressed  above  30  pounds 
absolute,  it  costs  6  per  cent,  with  ordinary  compressors.  Hence 
the  importance  of  good  compressors.  The  same  system  is 
carried  out  in  the  ordinary  water- tube  boiler  (Fig.  51).  This 
furnace  is  applicable  to  the  many  forms  of  water-tube  boiler. 
The  same  grate  cover  of  fire-brick  is  employed,  but  the  bars 


,"•  OIL  PIPE 

NAVY  GLOBE  VALVE 


2    '  AIR  PIPE 


TYPICAL  MOUNTING 
or 

CLASS  "LM"  BILLOW  ATOMIZER  9" 

Fig.   5  la. 

are  lowered  considerably  to  provide  room  for  the  concave 
bridge,  which  is  also  split  to  admit  air.  The  burner  points 
somewhat  down  so  as  to  strike  on  the  brick  floor  at  about  half 
length,  the  flames  curving  round  the  bridge  hollow. 

It  may  be  added  that  for  English  practice  the  containers 
of  oil  pumping  systems,  if  employed  in  preference  to  gravity 
feeds,  of  Fig.  45  type  should  be  of  boiler  plate  and  not  of  cast- 
iron — a  material,  the  use  of  which  for  pressure  work,  and 
especially  for  pressure  work  with  liquid  fuel,  is  considered 
indefensible,  and  would  probably  not  be  passed  as  safe  by 
the  English  boiler  insurance  companies.  Fig.  5 la  shows  a 
typical  boiler  mounting  on  the  Billow  system. 


CHAPTER    XIII 


ENGLISH   STATIONARY  PRACTICE   WITH   LIQUID   FUBL 

The  Kermode  System. 

IN  this  system  air  at  low  pressure  is  the  atomizing  agent, 
the  air  being  heated  in  a  thick  retort  pipe,  which  is 
carried  round  the  furnace  or  uptake. 

Oil  gravitates  from  an  overhead  tank,  as  very  usual  in 
marine  work.  It  flows  thence  by  a  IJ-in.  pipe  to  the  furnace 
front  and  separates  to  the  two  burners  by  equal  branching 
pipes.  Where  two  burners  are  supplied  off  one  pipe  the 
branches  to  each  must  be  symmetrically  arranged  in  order 
that  equal  supplies  of  oil  may  reach  each  burner. 

The  illustrations  represent  one  form  of  the  furnace  arranged 
by  the  Wallsend  Slipway  Co.  for  this  system,  the  lower 
part  of  the  marine  furnace  being  filled  with  special  fire-brick 
blocks  through  which  air  enters  the  furnace  beneath  the  flame. 
These  blocks  are  covered  with  asbestos  lumps  similar  to  the 
ordinary  grate  of  Fig.  53,  which  shows  an  alternative  arrange- 
ment including  also  an  oil  heating  pipe  in  the  furnace  in  addition 
to  the  air  heating  pipe. 

The  accompanying  table  of  tests  and  copy  of  analysis  of 
Borneo  oil  are  given  from  results  of  trials  at  the  Wallsend 
Company's  Works — 

COPY  OF  ANALYSIS  BY  DR.  GEORGE  TATE,  F.I.C,,  F.G.S., 
NOVEMBER  9,  1899. 


Sample. 

Astatki. 

Borneo 
Crude  Oil 
as  received. 

Borneo 
Crude  Oil 
dried. 

Water      

p.  c. 
trace 

p.  c. 
11-75 

p.  c. 

Carbon     

79-92 

73-60 

83-40 

Hydrogen 

12-00 

9-08 

10-29 

Oxygen  and  undetermined  elements 

8-08 

5-57 

6-31 

Total      

100-00 

100-000 

100-00 

Calorific  power  in  B.Th.U.  . 

18434 

15-894 

18-010 

Equivalent  evaporative  power 

19-0  Ib. 

16-41b. 

18-6lb. 

208 


209 


•s 


210 


ENGLISH  STATIONARY  PRACTICE 


211 


LiquiJFuat 
Pipe 


Oil 
An 

Fig.     53.     LIQUID     FUEL  FURNACE.     KERMODE'S     SYSTEM.      ALTERNATIVE 

ARRANGEMENT. 


Date  of  Trial. 

Sept.  6, 
1899. 

Sept.  14, 
1899. 

Sept  19,  1899. 

Duration  of  trial  

3  hours 

4  hours 

2  hours 

Class  of  oil  used   

Borneo 

Borneo 

Borneo  crude 

crude 

crude 

First  hour 

Second  hour 

Mean  pressure  on  boiler,  Ib. 

111 

110-5 

109-8 

110-4 

Total  Ib.  of  water  evaporated    . 

24,161 

35,323 

9362-5 

9511 

Pounds  evaporated  per  hour 

8053-7 

8830-75 

9362-5 

9511 

Pounds  of  water  per  pound  of  oil 

11-1 

10-9 

10-93 

10-92 

Ditto  from  and  at  212°F.     . 

12-9 

12-75 

12-85 

12-84 

Mean  temperature  of  feed  water 

deg.  Fahr  

89° 

89° 

83° 

83° 

Temperature  of  oil  in  measuring 

tank,  deg.  Fah  

68° 

68° 

67° 

67° 

Total  gallons  of  oil  consumed    . 

225-3 

337 

88-8 

90-2 

,,      pounds  of  oil  consumed   . 

2174 

3244 

856-5 

870-3 

Gallons  consumed  in  1  hour 

75-1 

84-2 

88-8 

90-2 

Pounds  consumed  in  1  hour 

724-7 

811 

856-5 

870-3 

Pressure  on  oil  at  burner  pound  . 

4-3 

4-3 

4-3 

4-3 

Specific  gravity  of  oil      ... 

•965 

•965 

•965 

•965 

Temperature  of  uptake  deg.  F.  . 

650° 

665° 

720°       !    720° 

Smoke  at  funnel  top. 

Light 

Light 

Light  brown 

brown 

brown 

Air  pressure  in  burner,  pounds 

3-2 

3-2 

3 

Revolutions  of  blowing  engine  . 

310 

350 

320 

Pounds  of  oil  per  sq.  ft.  of  grate 

18-1 

20-3 

21-5 

Pounds  of  water  per  sq.  ft.  of 

heating  surface       .... 

4-75 

5-5 

5-5 

7  -5  per  cent,  of  water  in  the  oil  is  allowed  for  in  the  above  results. 
This  seems  rather  excessive,  but  probably  explains  the  results. 


212         LIQUID  FUEL  AND  ITS  APPARATUS 

The  boiler  had  the  following  dimensions : — 

Mean  diameter 12  ft.  6  ins. 

Mean  length lift. 

Two  furnaces 3  ft.  7  ins.  inside  diameter. 

262  tubes  2£  ins.  external  diameter, 

8  feet  between  tube  plates 

Heating  surface  of  tubes  ....  1,372  sq.  ft. 

Furnaces 123 

Combustion  chambers 125 

Tube  plates 75 


Total 1,695 

Grate  area  of  one  surface.      ...  20 

Diameter  of  chimney 5  ft. 

Height  from  bars 55   „ 

The  burners  are  arranged  so  as  to  be  readily  swung  back 
when  coal  firing  is  to  be  resumed,  and  there  is  very  little  change 
to  the  furnace  in  the  system  of  Fig.  53.  Probably  the  light 
smoke  which  is  made  might  be  reduced  by  the  use  of  somewhat 
more  fire-brick  in  the  furnace  or  combustion  chamber. 

Tests  made  at  Birkenhead  are  said  to  have  shown  an  evapora- 
tion as  high  as  15-5  pounds  from  and  at  212°F.  per  pound  of 
Russian  astatki  and  without  smoke.  Borneo  oil  is  credited  by 
Dr.  Tate  with  less  hydrogen  than  usually  is  found  in  petroleum 
fuels,  the  average  formula  apparently  being  C7H]0.  The  latest 
burner  for  this  system  is  described  under  the  head  of  atomizers, 
Fig.  68. 

The  remarkable  thing  in  this  system  is  the  satisfactory  results 
obtained  with  only  3  pounds  of  air  pressure,  but  it  must  be  noted 
that  this  air  is  highly  heated.  The  above  trials,  made  many 
years  ago,  show  what  improvements  have  since  been  made  for 
to-day  (1911). 

The  following  figures  show  the  results  which  can  be  obtained 
on  a  steam  boiler  fitted  with  any  one  of  the  three  systems 
of  atomization  used  in  the  Kermode  system. 

Oil  fuel,  which  has  a  theoretical  calorific  value  of  19,320 
British  thermal  units  per  pound,  is  capable  of  evaporating  20 
Ib.  of  water  from  and  at  212°  F.  (theoretically)  for  every  pound 
of  oil  consumed,  and  if  the  air-jet  system  is  used,  from  15-6 
to  16-6  Ib.  of  water  can  be  evaporated  per  pound  of  oil  consumed 
under  practical  working  conditions.  That  is  to  say,  from  78 
per  cent,  to  83  per  cent,  of  the  theoretical  calorific  value  of  the 
oil  is  recovered  for  useful  work. 

The  pressure-jet  system  will  recover  from  70  per  cent,  to  75 
per  cent,  of  the  theoretical  calorific  value  of  the  oil  fuel  used  in 
actual  practice.  That  is  to  say,  with  oil  fuel  of  19,320  B.Th.U.'s 


213 


214          LIQUID  FUEL  AND  ITS  APPARATUS 

per  lb.,  the  evaporation  per  pound  of  oil  consumed  would  be 
from  14  to  15  lb.  of  water  per  lb.  of  oil  consumed. 

The  steam-jet  system  will  recover  from  68  per  cent,  to  74 
per  cent,  of  the  calorific  value  of  the  fuel  used,  or  a  pound  of 
oil  foul  will  evaporate  from  13-6  to  14  8  lb.  of  water. 

For  dealing  with  the  by-product  (tar)  from  the  Mond  Gas 
power  plant,  the  Kermode  system  converts  a  hitherto  useless 
refuse  to  liquid  fuel,  and  by  this  means  an  enormous  saving  is 
effected  in  the  fuel  bill  of  Mond  Gas  plants. 

The  Kermode  system  embraces  all  three  methods  of  atomiza- 
tion  by  air,  by  steam  and  by  oil  pressure,  without  other  agency, 
the  oil  spraying  itself  by  its  own  energy.  An  example  of  each 
type  of  sprayer  will  be  found  in  the  chapter  on  atomization. 

In  Fig.  54  is  shown  a  recent  Kermode  furnace  as  arranged 
under  a  Babcock boiler,  on  a  test  of  which  13-32  lb.  of  water  is 
stated  to  have  been  evaporated  at  1 00  lb.  pressure  from  feed  at 
64-4°F.  per  lb.  of  oil,  the  efficiency  being  79-65  per  cent. 

The  burners  themselves  are  shown  at  A,  the  air  pipes  at  B, 
the  oil-pipes  at  C,  the  oil-main  at  D  and  E,  the  air-mains  at 
G,  from  which  the  branch-pipes  A  go  to  the  burners,  and  the 
air-compressor  at  M,  from  which  the  air  passes  along  the  pipe 
to  the  heater  K.  An  air  by-pass  valve  is  shown  at  N,  and  air- 
pipes  0,  0,  which  lead  to  the  flue  and  discharge  the  surplus  air 
when  required.  The  results  have  quite  come  up  to  expectation, 
for  the  evaporation  from  and  at  212°F.  has  proved  to  be 
15-91  lb.  of  water  per  pound  of  fuel,  although  the  oil  was  not  of 
a  very  high  calorific  value. 

During  test  mentioned  the  water  evaporated  per  hour  was 
at  the  rate  of  1362-5  kilogrammes  (3,004  lb.)  per  hour.  The 
pressure  of  the  air  supplied  to  the  burners  was  0-7  lb.  per 
square  inch,  with  very  slight  variations.  The  temperature 
of  the  feed- water  was  64  4°F.,  and  that  of  the  liquid  fuel 
69-8°F.  The  amount  of  oil  consumed  during  the  eight  hours' 
test  was  1,801  lb.,  and  the  total  amount  of  water  evaporated 
was  23,980  lb.  The  Kermode  system  is  applied  equally  to 
land  or  marine  work,  and  to  fire  engines  and  small  work,  and 
any  liquid  fuel  is  utilized,  notably  the  tar  of  the  Mond  Gas 
producer. 

Numerous  large  and  small  vessels  of  the  Navy  have  been 
fitted  with  this  system. 

The  Hydroleum  System. 

In  this  system  great  stress  is  laid  upon  the  spraying  of  the 
oil  through  a  comparatively  restricted  area  or  passage  upon  a 


ENGLISH  STATIONARY  PRACTICE  215 


Fig.  55.     WATER  TUBE  BOILER  WITH  HYDROLEUM  LIQUID  FUEL  SYSTEM. 

dash-brick,  which,  it  is  claimed,  becomes  highly  heated  and 
vaporizes  the  spray.     This  is  shown  in  Fig.  55. 

Tested  with  water  gas  tar  at  the  works  of  Messrs.  Muirhead  & 
Co.,  Elmer's  End,  Kent,  the  following  results  were  obtained  : — 

Oil.  Coke. 

Date Aug.  14,  1901.    May  15,  1901. 

Duration  of  test 2  hours  9  hours 

Mean  temperature  of  feed  water.      .  70  Fahr.  60  Fahr. 

Mean  pressure  on  boiler    .      .      .  90  Ib.  90  Ib. 

Pounds  of  water  evaporated  .      .      .  2,400  10,100 

„       consumed     ...  211  1,792 

Pounds  of  water  evaporated  per  Ib. 

from  and  at  212°F 13-47  6-73 

Price  of  tar 19s.  Q$d.  per  ton  =  402d.  per  Ib. 

Price  of  coke 21s.  Sd.    per  ton  =  -116d.  per  Ib. 

N.B. — In  making  the  test  the  tar  was  taken  as  received,  no 
deduction  being  made  for  any  water  it  contained. 
Comparing  these  two  tests  it  will  be  seen  that : — 

To  evaporate  each  pound  of  water  with  coke  cost     .      0-0172df. 
To  evaporate  each  pound  of  water  with  water  gas  tar   0-0075d. 

Saving  by  the  system  of  oil  firing 0-0097d.  per  Ib. 


216         LIQUID  FUEL  AND  ITS  APPARATUS 

The  burner  of  this  system  will  be  found  described  under  the 
head  of  atomizers,  but  the  Hydroleum  Company  do  not  profess 
to  atomize.  They  lay  stress  upon  the  use  of  a  dash-brick  only 
about  18  inches  in  front  of  the  spray  nozzle,  an  intense  local 
heat  being  developed  on  the  face  of  the  brick.  Sufficient  air 
to  burn  the  vaporized  oil  is  induced  through  the  openings 
provided  round  the  spray  nozzle.  The  sprayer  is  made  in  three 
sizes,  having  capacities  of  1,  3,  and  10  to  12  gallons  of  oil  per 
hour,  and  the  oil  is  induced  to  flow  by  the  inductive  action  of 
the  steam  annulus.  The  feed  tank  is  kept  at  a  level  of  half  an 


Fig.  56.     HYDBOLEUM  LIQUID  FUEL  SYSTEM.     MAHINE  BOILEK  DESIGN. 


inch  below  the  nozzle  by  means  of  a  ball  float  valve.  From 
14*5  to  15  pounds  of  water  are  stated  to  be  evaporated  from  and 
at  212°F-  per  pound  of  oil,  the  expense  of  steam  being  5  per 
cent,  of  the  evaporation. 

Though  not  claimed  as  an  atomizing  system,  the  Author 
considers  that  the  effects  of  the  Hydroleum  burner  sufficiently 
resemble  atomizing  for  this  burner  to  be  held  up  as  an  example 
of  the  success  of  the  system. 

Experience  shows  that  for  a  burner  capable  of  burning  10 


ENGLISH  STATIONARY  PRACTICE  217 

gallons  per  hour  there  should  be  an  opening  for  air  round  the 
atomizer  of  8"  x  8",  which,  after  deducting  the  cross  section 
of  the  atomizer  itself  leaves  sixty  square  inches  of  air  opening 
for  ten  gallons  per  hour.  Worked  out  on  the  basis  of  15  Ib.  of 
air  per  Ib.  of  oil  fuel  and  13  cubic  feet  per  Ib.  the  velocity  per 
second  of  the  air  stream  is  only  13  feet.  A  gallon  of  fuel  is 
taken  as  10  Ib.,  which  is  about  correct  for  tar.  The  amount 
of  fuel  fed  is  simply  regulated  by  the  amount  of  steam  used, 
and  this  draws  in  more  or  less  air  as  required  by  the  fuel,  and 
very  little  regulation  of  the  air  inlets  is  required.  A  trunk 
casing  is  placed  round  each  burner  with  opening  downwards  to 
reduce  noise.  This  gives  very  effectual  silencing.  These  air 
trunks  may  be  all  coupled  to  a  common  air  main  brought  from 
outside  the  building.  As  seen  by  the  Author,  burning  oil  gas 
tar  of  Sp.  Gr.  1-04  in  a  Lancashire  boiler  the  system  was  smoke- 
less and  very  silent.  The  Hydroleum  atomizer  will  be  found 
described  in  the  chapter  on  atomizers. 


CHAPTER  XIV 

THE   COMBUSTION   OF  VAPORIZED   LIQUIDS 

The  Clarkson  and  Capel  Burner. 

IN  this  burner  system  the  liquid  employed  is  preferably  the 
cheaper  and  commoner  qualities  of  lamp  oil.  The 
burner  shown  (Fig.  57)  is  one  that  is  fitted  to  floating  fire 
engines.  It  is  capable  of  burning  40  gallons  of  oil  per  hour 
and  of  developing  up  to  200  h.p. 

There  is  a  gas  ring  to  give  the  initial  heat  to  vaporize  the  oil. 
The  jets  heat  the  coils  to  which  the  oil  is  fed,  and  the  vapour 
passes  from  the  coil  to  the  rear  of  the  long  casting,  which  it 
enters  through  a  small  orifice  controlled  by  a  needle  point. 
Air  is  admitted  by  a  door  at  the  back  end  and  the  vapour  and 
air  are  thoroughly  mixed  in  the  pipe  and  issue  round  the  lip 
of  the  mushroom  valve,  where  ignition  takes  place  and  a  large 
flaring  flame  of  great  intensity,  is  formed,  the  heat  from  which 
now  vaporizes  the  oil  in  the  coil,  and  the  process  is  continuous. 
The  oil  is  under  pressure  in  the  supply  tank,  the  pressure  being 
generated  by  an  air  pump.  The  pressure  forces  the  oil  through 
the  system,  and  when,  in  vaporized  form,  this  reaches  the  jet 
nozzle,  it  issues  with  a  high  velocity  and  induces  a  large  flow 
of  air  through  the  valve.  The  needle  of  the  jet  nozzle  is  worked 
by  the  same  controlling  lever  as  regulates  the  cap  of  the  burner. 
In  the  course  of  this  lever,  which  is  of  compound  order,  is  a 
maximum  and  minimum  stop  that  can  be  regulated  to  prevent 
•excessive  opening  or  entire  extinguishing  of  the  flame.  The 
hand  wheel  of  the  larger  burner  in  Fig.  57  shows  how  this  is 
effected. 

In  the  automobile  pattern  (Fig.  58)  the  initial  heating  device 
is  a  spirit  trough  containing  a  coil  of  nickel  wire.  Petrol  or 
alcohol  can  be  employed.  The  burner  is  placed  in  the  cylindrical 
base  of  the  boiler  ;  the  case  bottom  is  perforated  for  air  admis- 
sion and  provided  with  a  door  for  inspection. 

A  system  of  preliminary  heating  by  means  of  paraffin  con- 
sists of  a  series  of  asbestos  wicks  provided  with  an  air 

218 


219 


220          LIQUID  FUEL  AND  ITS  APPARATUS 


draught  by  a  small  fan    and  fed  with  a  limited  quantity  of 

paraffin  from  a  small  cup,  the  main  supply  of  oil  being  heated 

in  the  f-inch  coil. 
After  the  cupful  of 
paraffin  is  finished  the 
flame  of  the  main 
burner  will  be  burning 
and  will  provide  heat 
for  further  vaporiza- 
tion. 

For  use  in  automo- 
biles, small  steam-boats, 
the  cheap  forms  of 
lamp  oil  are  commerci- 
ally practicable,  though 
they  would  be  too  ex- 
pensive for  ordinary 
continuous  industrial 
steam  raising  purposes. 
For  other  reasons  these 
oils  commend  them- 
selves for  the  purposes 
of  fire  engines  and  fire 
floats.  Here  the  use  of 
expensive  fuel  is  war- 
ranted by  the  nature  of 
the  service,  namely,  the 
extinguishment  of  a  fire 
that  may  be  consuming 
valuable  buildings  and 
their  contents.  Even 
the  lighter  petrols  are 
used  for  steam  raising 
purposes  in  certain 
forms  of  steam  cars, 

)  Inf  the  petrol  being  sprayed 

upon  a  hot  cast  iron 
plate  through  which  fine 
jets  of  air  are  intro- 
duced and  the  heat  is 
utilized  to  raise  steam 
in  coil  boilers  of  the 

flash  type  into  which  water  is  injected  to  provide  the  steam 

for  instant  use. 

In  the  Clarkson   system  one  pound  of   oil  can  be  counted 


THE  COMBUSTION  OF  VAPORIZED  LIQUIDS     221 

upon  to  give  an  evaporation  of  10  pounds  of  water  from  80°C., 
to  steam  at  200  pounds,  or  an  equivalent  evaporation  from  212° 
F.  of  nearly  11  pounds.  The  oil  receptacle  is  usually  worked 
at  a  pressure  of  40  pounds,  and  the  cheaper  grades  of  Russian 
oil  are  perhaps  the  most  suitable,  such  as  Rocklight,  Lustre,  etc. 

As  stated  elsewhere,  the  calorific  capacity  of  all  the  petroleum 
products  is  practically  identical,  the  lighter  oils  being  more 
powerful  because  they  contain  the  highest  percentage  of  hydro- 
gen, but  the  difference  is  immaterial.  The  evaporative  effici- 
ency of  the  small  boilers  of  cars  and  canoes,  is  less  than  that  of 
large  boilers  simply  because  it  is  not  desirable  to  load  up  a  car 
with  too  great  a  weight  of  heating  surface. 

In  the  starting  device  employed  on  automobile  cars,  a  pad 
fed  with  a  drop  feed  of  oil  is  ignited  by  a  match  and  gives  pre- 
liminary heat  to  the  burner. 

The  combustion  of  petrol  is  a  special  case  of  vaporization 
before  combustion.  Petrol  has  such  a  low  flash  point  that  it 
is  absorbed  by  air  passing  over  it,  with  great  avidity. 

Petrol  engines  are  simply  gas  engines  with  electric  ignition 
which  use  petrolized  air.  The  petrol  is  fed  into  a  vessel  called 
the  carburettor  in  small  quantities  by  the  action  of  a  float,  and 
it  is  taken  up  by  a  stream  of  air  which  is  drawn  through  the 
vessel  by  the  pistons  of  the  engine.  The  petrol  is  used  as 
supplied.  Petrol  being  a  mixture  of  different  hydrocarbons 
with  each  its  own  flash  point,  no  system  of  petrolizing  of  air 
can  be  satisfactory  where  the  air  is  drawn  over  a  mass  of  petrol, 
for  the  air  will  select  first  the  lighter  constituents  and  leave 
the  heavier  behind.  In  all  cases  the  petrol  must  be  put  within 
reach  of  the  air  in  small  quantities  at  once,  so  that  the  whole 
portion  added  is  carried  off  by  the  stream  of  air  before  more  is 
added.  The  evaporation  by  the  air  produces  a  chilling  effect 
and  raises  the  flash  point  of  the  liquid.  Carburettors  must 
therefore  be  warmed  by  a  hot  water  jacket  or  by  the  exhaust 
gases  of  the  engine. 

The  lamp  oil  qualities  of  paraffin  may  be  atomized  by  air 
into  the  space  below  a  perforated  disc  of  metal  forming  the 
cover  of  a  shallow  drum.  The  vaporized  paraffin  issues  from 
the  slits  of  the  burner  plate  and  burns  with  a  blue  Bunsen 
flame  and  this  burner  is  used  for  small  boilers  of  the  flash  type. 
The  flame  keeps  the  burner  plate  hot  enough  to  vaporize  the 
paraffin  in  the  space  below.  An  initial  heater  is  necessary  for 
starting  the  burner. 


CHAPTER   XV 

COMPARISON   OF  AIR  AND   STEAM  ATOMIZATION 

The  Ellis  and  Eaves  System. 

IN  this  system,  the  atomizing  is  done  by  steam,  and  heated 
air  is  supplied  to  the  furnaces,  the  draught  being  fan 
induced.  The  air  is  heated  in  tubular  heaters  having  two- 
thirds  of  the  boiler  heating  surface,  and  placed  over  the  boiler 
in  the  course  of  the  gases  to  the  fan,  as  shown  in  Fig.  59  ;  the 
admission  of  air  to  the  furnaces  being,  as  in  Fig.  60,  round  the 
outside  of  the  atomizer. 

Tests  were  also  made  with  air  as  the  atomizing  agent. 
The  air  pressure  was  20  pounds  per  square  inch,  and  the  results 
are  given  below.  A  subsequent  test  with  air  at  35  pounds 
pressure  showed  11,108  pounds  of  water  per  hour  from  and  at 
212°F.  per  pound  of  coal  and  15-49  pounds  per  pound  of  oil.  This 
is  somewhat  less  than  with  air  at  the  more  moderate  pressure  of 
20  pounds.  The  atomizing  air  had  a  temperature  of  80°F. 
only,  or  it  might  have  given  better  results. 

The  difference  between  steam  and  air  atomizing  seems  to  be 
practically  nil.  For  land  work  it  remains  simply  to  compare 
the  amount  of  steam  used  direct  with  that  used  in  compressing 
the  air. 

The  analysis  of  the  flue  gases  showed  a  mean  result  of  11-2 
per  cent,  of  C02  and  10  per  cent,  of  oxygen  in  the  left  hand 
furnace  and  14-1  per  cent,  of  C02  and  8-4  of  oxygen  in  the 
right  hand  furnace,  the  mean  of  both  being  C02  =  12-6, 
0=9-6,  C0=0. 

The  tests  made  with  this  system  of  induced  draught  and  oil 
fuel  burning,  of  six  hours'  duration,  were  a  success,  but  the 
question  was  raised  whether  the  system  could  be  worked  for  a 
lengthened  period  without  giving  trouble  through  deposits  of 
soot  and  unconsumed  oil  becoming  ignited  in  the  air  heater  and 
casings,  and  a  continuous  test  of  120  hours  was  made,  careful 
observations  being  taken  of  the  temperatures,  evaporations,  etc. 


AIR  AND  STEAM  ATOMIZATION 


223 


Particulars  of  boiler,  wli3li  were  the  same  as  in  the  previous 
tests — 

12  ft.  mean  diameter  by  11  ft.  mean  length,  fitted  with  two 
Purves  furnaces  of  3  ft.  9  in.  inside  diameter. 


Fig.  59.     ELLIS  AND  EAVES  SYSTEM,  MARINE  BOILER  ARRANGEMENT,  FOR 

HEATING  AIR. 


148  Serve  tubes,  3|  in.  outside  diameter  by  7  ft.  9  in.  long 
and  retarders. 

Heating  surface,  1,200  sq.  ft.  Grate  surface  (for  coal  burn- 
ing) 43  sq.  feet. 


POSIT/OH  or  On  Buaticitf 


Valves  open  for -ft 
all  tests 


Fig.   60.     ELLIS  AND  EAVES  SYSTEM,  FURNACE  DOOR  ARRANGEMENT. 


Ratio  of  H.S.  to  G.S.     28  to  1. 

Fitted  with  the  Ellis  and  Eaves  system  of  induced  draught. 
Surface  in  air  heating  tubes,  800  sq.  ft. 
Diameter  of  Fan  wheel,  7  ft.  6  in. 


224          LIQUID  FUEL  AND  ITS  APPARATUS 

The  boiler  feed  supply  was  taken  from  two  tanks,  each  of 
800  gallons  and  two  oil  supply  tanks  for  burners,  having  a 
capacity  of  about  900  gallons  each  were  provided.  The  oil 
was  fed  to  burners  at  75°F. 

Steam  to  the  burners  was  supplied  at  70  pounds  per  square 
inch.  Texas  oil  was  used,  closed  flash  point  185,  calorific 
value  18400  B.Th.U.  Sp.  gr. '0-915. 

Smoke  was  visible  for  a  few  seconds  when  changing  over  the 
oil  tanks  about  every  eight  hours.  Heated  air  was  provided  ; 
the  difference  in  right  and  left  hand  temperatures  of  air  entering 
the  fires  being  due  to  the  fact  that  the  right  hand  air  heating 
box  and  air  casings  are  protected  from  the  weather  by  a  wall, 
and  also  that  the  air  entering  these  is  at  a  higher  temperature, 
due  to  radiation  from  the  fan  discharge. 

The  test  was  started  on  Monday,  December  15,  1902,  at 
eleven  a.m.,  the  boiler  being  cleaned  before  starting,  and  was 
continued  night  and  day  till  eleven  a.m.  on  Saturday,  December 
20,  the  installation  working  without  a  hitch  during  the  whole 
of  that  time.  Burners  required  cleaning  occasionally,  but 
this  was  carried  out  one  at  a  time,  and  only  occupied  a  few 
minutes.  Hot  air  was  admitted  to  the  furnaces,  the  greater 
portion  of  this  only  being  admitted  round  about  the  burners 
through  vena-contracta  nozzles. 

At  the  end  of  the  trial  the  boiler,  air  heater  casings,  etc., 
were  opened  up  and  examined  by  representatives  of  the  Wall- 
send  Slipway  Co.  and  the  International  Mercantile  Marine  Co., 
and  found  to  be  perfectly  clean  and  in  good  order,  there  being 
no  indication  of  flaming  in  the  casings.  From  the  foregoing 
and  a  perusal  of  the  following  tables,  the  perfect  combustion 
of  the  oil  may  be  attributed  to  the  use  of  heated  air  ;  no  smoke 
is  formed  and  there  is  no  deposit  of  inflammable  oil  or  soot  on 
the  tubes  or  casings  to  take  fire. 

From  the  table  on  page  227  the  advantages  of  air  heating  are 
shown  up  clearly.  Air  which  enters  the  heater  at  about  54 °F. 
leaves  it  at  about  284°F.,  having  taken  up  230°  of  temper- 
ature, all  of  which  is  absorbed  from  the  furnace  gases,  which 
are  reduced  from  about  760°F.  to  520°F.  more  or  less.  They  lose 
the  230°  gained  by  the  air,  and  this  alone  represents  a  very 
considerable  economy,  something  like  33  per  cent,  of  the  other- 
wise waste  heat  passing  up  the  chimney.  The  fan  efficiency 
is  also  increased.  Assuming  that  the  furnace  temperature  is 
2,800°F.  the  heating  of  the  air  by  the  waste  gases  would  appear 
to  represent  an  economy  of  fuel  of  8  to  10  per  cent.,  apart 
from  the  higher  boiler  efficiency  'due  to  increased  temperature 
head. 


AIR  AND  STEAM  ATOMIZATION 


225 


Air  heating  is  thus  advantageous  both  in  economy  and  more 
perfect  combustion. 


STEAM  ATOMIZATION. 


Time. 

Steam 
Pres- 
sure. 

Fan 
Revo- 
lutions 

Vac- 
uum 
at 
Fan 
Suc- 
tion, 

Vac- 
uum 
at 
Fur- 
nace. 

Tem- 
per- 
ature 
of  Air 
enter- 
ing 
Heater. 

Heated  Air 
entering  Fires. 

Escap- 
ing 
Gases 
entering 
Air 
Heater. 

Escap- 
ing 
Gases 
at 
Fan 
Suction. 

Feed 
Water 
Tem- 
per- 
ature. 

Water 
Time 
taken  to 
empty 
Tanks. 

Oil. 
Gals. 

Left. 

Right. 

Tank 
Mins. 

Tank 
2. 

Mins. 

10-0 

145 

305 

2J* 

r 

75°F. 

235°F. 

300°F. 

700°F. 

475°F. 

60°F. 

46 

10.30 

135 

309 

2r 

r 

75° 

235° 

290° 

700° 

475° 

60° 

49 

82$ 

11.0 

140 

308 

2J" 

r 

75° 

232° 

285° 

695° 

470° 

55° 

11.30 

135 

305 

2i" 

r 

75° 

230° 

285° 

695° 

470° 

58° 

55 

80 

12.0 
12.30 

140 

300     2£* 

r 

75° 

227° 

275° 

675° 

455° 

58° 

137 

299     2J* 

r 

75° 

233° 

275° 

700° 

460° 

58° 

41 
40 

81* 
100 
93| 

1.0 

140 

308 

21* 

r 

75° 

242° 

295° 

715° 

485° 

58° 

39 

1.30 

130 

302 

21" 

r 

75° 

247° 

305° 

710° 

490° 

58° 

2.0 

150 

305 

21* 

r 

75° 

248° 

308° 

715° 

490° 

58° 

2.30 

145 

305 

21" 

r 

75° 

248° 

305° 

715° 

485° 

58° 

40 

3.0 

140 

312 

21" 

r 

76° 

245° 

295° 

705° 

475° 

58° 

42 

3.30 

140 

310 

21" 

r 

75° 

245° 

290° 

705° 

485° 

58° 

135  gals, 
out  of 
last  tank. 
Total 
6,535  gals. 

82$ 

4.0 

145 

309 

21" 

r 

75° 

246° 

295° 

710° 

505° 

58° 

Total 
530. 

Water  evap.  per  hour. 
Actual  observed  conditions. 

10,891 
Ib. 

Water  evap.  per  Ib.  of  Oil. 
Actual  observed  conditions. 

134 

Ib. 

Water  evap.  per  hour, 
from  and  at  212°  Fah. 

13,145 

Ib. 

Water  evap.  per  Ib.  of  Oil 
from  and  at  212°  Fah. 

16-1 
Ib. 

Water  evap.  per  sq.  ft.  H.S. 
Actual  observed  conditions 

9 
Ib. 

Water  evap.  per  sq.  ft.  H.S. 
from  and  at  212°  Fah. 

10-9 
Ib. 

Theoretical  total  heat  value 
of  Oil  in  Ib.  of  water  from 
and  at  212°  Fah. 

19-14 
Ib. 

Efficiency  of  Boiler. 

84% 

The  steam  tests  were  of  6  hours'  duration,  those  with  air  of 
four  hours'. 

p 


226          LIQUID  FUEL  AND  ITS  APPARATUS 


AIR  ATOMIZATION. 


Time. 

Steam 
Pres- 
sure. 

Fan 
Revo- 
lutions 
per 
min- 
ute. 

Vac- 
uum 
at 
Fan 
Suc- 
tion. 

Vac- 
uum 
at 
Fur- 
nace. 

Tem- 
per- 
ature 
of  Air 
enter- 
ing 
Air 
Heater. 

Heated  Air 
entering  Fires. 

Escap- 
ing 
Gases 
entering 
Air 
Heater. 

Escap- 
ing 
Gases 
at 
Fan 
Suction. 

Feed 
Water 
Tem- 
per- 
ature. 

Water 
Time 
taken  to 
empty 
Tanks. 

Oil. 
Gals. 

Left. 

Right. 

Tank 
Min's. 
52 

Tank 
2 

Mins. 

10.30 

130 

297 

21" 

ii" 

74°F. 

220°F. 

225°F. 

600°F. 

360°F. 

50°F. 

11.0 

130 

297 

21* 

ir 

74° 

216° 

245° 

630° 

400° 

50° 

47 

68-4 
99-28 

11.30 

130 

300 

21" 

ii" 

74° 

225° 

250° 

630° 

410° 

50° 

12.0 

130 

300 

21" 

H* 

74° 

225° 

250° 

630° 

410° 

50° 

45 

12.30 

130 

298 

21" 

ii" 

74° 

223° 

250° 

630° 

410° 

50° 

1.0 

140 

298 

21" 

ii" 

74° 

223° 

250° 

630° 

410° 

50° 

45 

86-04 
83-83 

1.30 
2.0 

140 

298 

21* 

ir 

74° 

225° 

250° 

630° 

410° 

50° 

140 

298 

21* 

ir 

74° 

225° 

250° 

630° 

410° 

50° 

46 

2.30 

135 

298 

21* 

ir 

74° 

225° 

250° 

630° 

410° 

50° 

90  gallons 
taken  from 
last  tank. 

Total 
4,090  gals. 

Total 
337-55 

Water  evap.  per  hour 
Actual  observed  conditions. 

10,225 

Ib. 

Water  evap.  per  Ib.  of  Oil. 
Actual  observed  conditions. 

13-24 
Ib. 

Water  evap  per  hour, 
from  and  at  212°  Fah. 

12,413 
Ib. 

Water  evap.  per  Ib.  of  Oil 
from  and  at  212°  Fah. 

16-07 
Ib. 

Theoretical  total  heat  value 
of  Oil  in  Ib.  of  water  from 
and  at  212°  Fah. 

19-14 
Ib. 

Efficiency  of  Boiler. 

84% 

AIR  AND  STEAM  ATOMIZATION  227 


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CO  ^  O 
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i—  li—  !»O<N<NOOO''f<N'—  i(Ni—  (i—  ii—  i 


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CO  <N  —I  CO  CO  00  ^  "  O  V  ^ 


.s  .a  h  *,  •  •, 

'     »M      c  o       o 


CHAPTER    XVI 

THE    STORAGE   AND   DISTRIBUTION   OF  LIQUID   FUEL 

IN  carrying  or  storing  oil,  it  is  necessary  to  provide  for  its 
expansion,  and  it  is  also  necessary  to  provide  a  safeguard 
against  the  rupture  of  the  storage  tanks  unless  these  are  below 
ground  level.  Provision  must  also  be  made  for  the  escape 
of  any  gas  or  vapour  generated  from  the  oil  and  against  danger 
from  leakage. 

The  tanks  used  for  oil  storage  have  a  diameter  of  from  40 
to  70  feet.  Some  are  as  large  as  90  feet,  and  the  largest  will 
hold  over  one  million  gallons,  or  3,300  gallons  per  inch  of 
depth.  To  prevent  danger,  should  a  tank  fail,  it  ought  to 
be  surrounded  by  a  moat  capable  of  holding  the  contents  of 
the  tank.  Both  crude  oil  and  the  refined  products  are  now 
carried  in  specially  constructed  tank  steamers,  some  of  which 
will  carry  as  much  as  8,500  tons  of  oil. 

At  Liverpool  these  steamers  are  discharged  through  an 
8-inch  pipe  into  vertical  tanks  of  2,000  and  3,000  tons  capacity. 
The  carrying  space  in  the  steamers  is  formed  by  riveted  bulk- 
heads across  the  ship,  the  skin  of  the  ship  itself  forming  sides 
to  the  tanks,  the  screw  shaft  being  laid  in  a  tunnel.  Refined 
oil  possesses  such  penetrative  properties  that  the  riveting  of 
such  tanks  must  be  carefully  done,  and  the  rivet  spacing  is 
closer  than  in  ordinary  work.  The  tanks  ought  to  be  full  of 
oil,  and  they  must  not  be  too  large,  a  bulkhead  being  placed  at 
intervals  not  wider  than  24  feet.  These  bulkheads  must  be 
stiff  enough  to  stand  the  unsupported  pressure  of  the  liquid 
upon  one  side  only,  together  with  such  extra  stress  as  may  be 
caused  by  the  movement  of  the  vessel.  The  specific  gravity 
of  petroleum  varies  considerably,  but  an  approximate  rule 
to  cover  all  cases  of  oil  pressure  is  P  =  040  H,  where  P  is  the 
pounds  pressure  per  square  inch  and  H  is  the  depth  in  feet  below 
the  top  level  of  the  oil,  which  may  of  course  be  some  distance  up 
the  expansion  tanks. 

It  is  not  considered  safe  to  store  Texas  crude  oil  nearer  to 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  229 

boilers  than  500  feet,  and  in  case  of  a  spouting  well  all  fires 
within  500  feet  are  extinguished. 

Where  oil  is  used  freely  as  fuel  it  may  be  lead  to  the  different 
establishments  by  pipes  in  preference  to  carting  it  in  tanks. 
The  pipes  ought  to  be  of  wrought  iron  or  steel,  carefully  thread- 
ed and  fitted  together  with  sound  and  carefully  threaded 
sockets.  Pipe  joints  may  be  made  in  three  ways  :  (a)  The  pipes 
are  screwed  tapering  and  the  sockets  ought  to  be  threaded 
similarly  from  each  end  by  a  tapering  tap,  so  that  a  tight  joint 
may  be  secured  ;  (6)  Back  nuts  may  be  employed  to  reinforce 
the  sockets  by  aid  of  an  interposed  fibrous  ring  ;  (c)  The  pipe 
ends  may  be  truly  faced  off  exactly  at  right  angles  to  the  axis 
of  the  threading,  a  compressible,  but  thin,  washer  of  soft  metal 
or  fibre  being  interposed  between  the  ends  of  the  abutting 
pipes.  Such  pipes  meet  together  in  the  sockets  like  artesian 
drive  pipes. 

Ordinary  pipes,  if  found  to  leak  after  being  put  together, 
should  be  caulked  round  the  ends  of  the  sockets.  Before 
screwing  together  the  threads  ought  to  be  painted  with  some 
cement  not  soluble  in  petroleum.  Litharge  and  glycerine  is 
recommended.  Many  of  the  precautions  with  regard  to  oil 
arise  from  the  fact  thao,  being  lighter  than  water,  it  may  be 
carried  up  and  down  a  tidal  river  and  spread  a  general  conflag- 
ration. Being  liquid,  it  will  travel  by  gravity  to  long  distances. 
Where,  to  avoid  danger,  oil  is  stored  in  buried  vaults,  there  is 
danger  of  the  accumulation  of  explosive  vapours,  and  ventila- 
tion is  required  ;  the  outlet  of  a  ventilating  shaft  should 
be  well  exposed  and  out  of  such  danger  as  the  throwing  of  a 
lighted  match  from  some  point  above.  Where  ventilation 
does  not  take  place  freely,  it  might  be  necessary  to  use  positive 
means  of  drawing  out  the  air  from  a  tank  chamber  or  to  assist 
the  action  of  the  ventilating  trunk  by  a  warm  water  pipe  within 
it  and  a  swivelling  cowl  head. 

To  deal  with  the  liquid  fuel  locomotives  of  the  Great  Eastern 
Railway,  there  were  provided  a  series  of  underground  tanks  of  a 
capacity  in  the  aggregate  of  50,000  gallons,  filled  direct  from 
the  travelling  tanks  of  the  railway. 

From  these  underground  tanks  a  Tangye  Special  pump  lifts 
the  oil  to  cylindrical  tanks  20  feet  above  rail  level,  and  of  a 
total  capacity  of  42,000  gallons. 

Outlet  pipes  controlled  by  valves,  operated  from  a  gallery 
above,  conduct  the  oil  to  cranes  similar  to  an  ordinary  water 
crane. 

A  main  line  engine  will  take  in  600  gallons  of  oil  in  four  or 
five  minutes. 


230          LIQUID  FUEL  AND  ITS  APPARATUS 

Electric  lighting  is  employed,  with  portable  lamps  for  the 
cranes  or  filling  arms. 

Oil  may  be  stored  underground  only,  and  in  airtight  tanks, 
which  are  caused  to  supply  the  filling  arms  by  pumping  air 
into  the  tanks  above  the  oil,  the  air  brake  pump  of  the  locomo- 
tive itself  doing  this  work. 

The  tanks  of  the  tender  are  filled  through  a  fine  gauze  strainer, 
protected  by  a  perforated  cylinder,  so  that  everything  in  the 
shape  of  an  obstruction  is  filtered  out,  and  the  gauze  also 
serves  to  prevent  ignition  of  any  possible  vapour  in  the  tank, 
acting  to  prevent  this  on  the  well  known  principle  of  the  miner's 
safety  lamp.  This  precaution  is  more  necessary  where  crude 
oils  are  used  than  for  the  higher  flash  point  residues. 

On  the  Grazi  and  Tsaritzin  Railway  Mr.  Urquhart,  in  his 
1884  1  paper  gave  the  length  of  line  worked  with  petroleum  as 
from  Tsaritzin  to  Burnack,  291  miles,  and  a  total  of  423  miles, 
including  the  Volga-Don  branch.  There  is  a  main  reservoir 
for  petroleum,  at  each  of  the  four  engine  sheds,  66  feet  diameter 
and  24  feet  high,  and  about  2,050  tons  capacity.  The  reservoir 
stands  a  good  way  from  the  line  and  from  dwelling  houses  and 
buildings. 

On  a  special  siding  are  placed  10  cistern  cars  full  of  oil,  the 
capacity  of  each  being  about  10  tons.  From  each  car  a  connec- 
tion is  made  by  a  flexible  india-rubber  pipe  to  one  of  the  ten 
standpipes,  which  project  one  foot  above  the  ground  line. 
Parallel  with  the  rails  is  laid  a  main  pipe,  with  which  the  ten 
standpipes  are  connected,  thus  forming  one  general  suction 
main.  About  the  middle  of  the  length  of  the  main,  which  is 
laid  undergound  and  covered  with  sawdust  or  other  non- 
conducting material,  is  a  steam  pump  which  in  about  one  hour 
discharges  the  whole  of  the  cars  into  the  main  reservoir.  The 
pipes  are  all  wrought  iron,  lap  welded,  5  inch  socketed. 

At  each  shed  there  is  an  elevated  tank  (Fig.  61)  8 J  feet  dia- 
meter by  6  feet  deep,  built  of  J  in.  plate,  to  serve  as  a  distribut- 
ing tank  to  the  locomotives.  A  divided  scale  shows  exactly 
how  many  poods  2  of  oil  have  been  drawn  out,  the  amount 
being  corrected  for  temperature  at  intervals  of  8°R.  =  18°F. 
— 10°C.,  the  scale  ranging  from  24°R.  to  -  24°R.  —  86°F. 
to  —  22°F.,  the  quantity  and  temperature  being  entered  in  the 
driver's  book.  The  heaviest  refuse  has  a  specific  gravity  of 
0-921  at  0°C.  =  32°F.,  so  that  39  cubic  feet  measure  one  ton, 
or  57-4  pounds  =  1  cubic  foot.  Lighter  refuse  has  a  specific 

1  Proceedings  of  the  Institution  of  Mechanical  Engineers,  1884. 

2  1  pood  =  36-114  English  pounds  =  40  pounds  Russian.      62'0257 
poods  =  1  ton. 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  231 


Distributing     Tank        /.\ 
.,' 


WFett 


Fig.    61.      DISTRIBUTING  TANK  FOR  OIL  FUEL.      GRAZI  AND   TSARITZIN 

RAILWAY. 


gravity  of  0889  =  40 J  cubic  feet  per  ton,  or  55 J  pounds  per 
cubic  foot. 

The  engineer-in-charge  at  each  station  is  provided  with  a 
hydrometer  and  thermometer  to  deal  with  the  ten  different 
grades  of  liquid,  each  grade  having  its  own  peculiar  sp.  gr.  and 
co-efficient  of  expansion.  Table  XIII  gives  useful  information 
on  this  subject. 

Oil  Pumps. 

Any  pump  which  will  pump  water  will  pump  oil,  if  not  too 
viscid.  So  long  as  an  oil  is  free  from  the  more  volatile  hydro- 
carbons, it  can  be  lifted  by  suction  from  a  depth  greater  than 
is  possible  with  water,  in  inverse  ratio  to  its  specific  gravity. 
By  weight  a  pump  will  throw  less  oil  than  water,  but  it  should 
throw  an  equal  volume. 

For  rapidly  transferring  large  bodies  of  oil  from  a  ship  to  a 
storage  tank,  the  centrifugal  pump  is  very  convenient.  There 


232         LIQUID  FUEL  AND  ITS  APPARATUS 

are  also  numerous  other  rotary  pumps  of  the  positive  propulsion 
type  similar  to  the  Roots'  Blower.  But  viscid  oil  can  hardly 
be  moved  by  a  centrifugal  pump. 


Fig.  62.     WEIR'S  OIL  PUMP. 


Valves  of  india-rubber  must  of  course  be  avoided,  and  only 
such  substances  employed  as  will  resist  the  solvent  action  of 
the  oil.  Metal  valves  should  prove  most  generally  durable  and 
efficient.  Simplicity  and  reliability  are  the  characteristics 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  233 

desired  in  a  pump.  For  bunker  filling  especially  the  pump 
must  be  of  ample  capacity,  so  that  a  ship  may  not  be  long 
detained  when  calling  for  fuel  in  port. 

An  example  of  a  bunkering  pump  is  the  Weir  Patent  Pump 
for  oil  pumping  as  shown  in  Fig.  62.  This  is  of  the  direct 
double-acting  type.  The  valve  gear  is  positive,  i.e.  the  steam 
valve  can  never  be  in  such  a  position  that  the  pump  will  not 
start  immediately  after  the  steam  is  turned  on.  The  valve 
arrangements  also  ensure  constant  length  of  stroke  and  cer- 
tainty of  action. 

The  steam  valve  consists  of  a  "  D  "  slide  valve  with  a  small 
auxiliary  valve  working  on  the  back.  These  are  the  only 
moving  parts  proper  in  the  steam  chest,  so  that  there  is  little 
opportunity  for  wear  and  no  delicate  adjustments  to  get  out 
of  order. 

The  oil  end  as  shown  is  fitted  with  Weir  group  valves, 
which  provide  a  large  area  with  only  a  small  lift,  thus  ensuring 
easy  working  and  little  wear  and  tear.  In  more  recent  types 
these  valves  are  of  the  Kinghorn  type  and  the  discharge 
branches  look  upward,  not  outward.  In  larger  sizes  the 
piston  rods  are  divided,  and  the  two  are  connected  by  a  screwed 
crosshead. 

The  pump  is  specially  economical  in  steam  consumption, 
and  is  simple  and  with  all  its  parts  easily  accessible.  The 
front  elevation  shows  that  there  is  a  separate  valve  chamber 
for  each  end  of  the  pump  cylinder,  the  valves  being  grouped 
on  the  valve  plate  round  a  central  valve.  With  long  pump 
buckets  there  should  be  no  need  to  use  rings.  The  bucket 
simply  requires  to  be  turned  a  good  but  free  fit  in  its  barrel 
and  grooved  with  square  edged  grooves  J"  wide  x  TfV"  deep, 
spaced  about  | \"  centres.  This  plan  is  very  effectual  with  water, 
and  should  be  perfect  for  oil  of  the  consistency  of  fuel  oil. 

FLUE  GAS  ANALYSIS. 

The  analysis  of  flue  gases  is  undertaken  for  the  purpose  of 
showing  the  perfection  of  the  combustion  and  the  excess  of  air 
employed. 

Considering  that  about  9  per  cent,  more  coal  is  consumed  if 
the  percentage  of  C02  is  8  per  cent,  instead  of  13  per  cent.,  the 
waste  of  coal  will  amount  to  900  tons  a  year  in  10,000  tons 
burned.  Oil  stands  on  the  same  level. 

In  practice,  about  1  -3  times  the  theoretical  quantity  of  air  is 
required  to  effect  perfect  combustion. 

How  much  coal  is  wasted,  if  the  percentage  of  carbonic  acid 


234          LIQUID  FUEL  AND   ITS  APPARATUS 

gas  falls  to  a  low  level,  may  be  seen  at  a  glance  from  the  follow 
ing  table — 


Percentage     of 

C02    .      .      . 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

Loss  of  fuel  in 

per     cent. 

against    the 

theoretically 

lowest     pos- 

sible quantity 

90 

60 

45 

36 

30 

26 

23 

20 

18 

16 

15 

14 

13 

12 

It  is  not  possible  to  tell  from  the  appearance  of  the  fire  in  the 
furnace  the  percentage  of  C02. 

As  one  pound  of  carbon  requires  a  minimum  of  11 J  pounds  of 
air  for  perfect  combustion,  it  will  produce  12 J  pounds  of  total 
furnace  gas,  and  of  this  3|  pounds  will  be  C02  :  that  is,  fully 
29  per  cent,  by  weight  or  nearly  21  per  cent,  by  volume.  For 
anthracite  coal  free  from  hydrogen  the  excess  of  air  can  be 
calculated  from  the  percentage  of  C02  in  the  flue  gas. 

For  fuels  containing  hydrogen,  the  analysis  being  done  cold, 
the  steam  which  is  produced  by  the  hydrogen  is  therefore  not 
measured,  this  steam  is  less  in  volume  than  the  nitrogen  of  the 
air  which  supplied  oxygen  to  burn  the  hydrogen.  The  per- 
centage of  CO2  in  the  flue  gas  thus  appears  smaller  with  the 
more  hydrogenous  fuels  than  it  does  with  the  less  hydrogenous 
fuel.  But  in  every  case  the  actual  percentage  can  be  calculated, 
and,  once  known,  subsequent  records  can  be  compared  with 
the  calculated  datum  line. 

A  fuel  containing  hydrogen  to  the  extent  of  one  per  cent, 
demands  55-9  litres  of  oxygen  per  kilo,  of  coal,  or  0-9  cubic 
foot  per  pound,  to  satisfy  the  hydrogen. 

The  following  tabular  numbers  give  the  volume  of  oxygen  per 
kilo,  and  per  pound  of  coal  for  various  percentages  of  hydrogen. 

Per  cent.  Litres  per  kilo.  Cubic  ft.  per  Ib. 

1 55-9 0-9 

2 112-0 1-8 

3 168-0 2-7 

4 223-0 3-6 

5 279-0 4-5 

6 336-0 5-4 

7 391-0 6-3 

8 446-0 7'2 

9 504-0 8-1 

10 559-0 9-0 

11 615-0 9-9 

12 672-0 10-8 

13  ....   .   .  727-0 11-7 

14 782-0 12-6 

15 837-0 13-5 

16  892-0  14-4 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  235 

In  calculating  the  volume  of  dry  gas  from  analysis,  any 
hydrocarbon  gas  is  calculated  as  though  it  were  simply  carbon 
vapour  of  a  weight  of  1-072  grams  per  litre. 

At  0°C.  and  760  mm.  pressure, 
Molecular  weight 

1  litre  of  CO2  =  1-966  gram  =  44. 

1     „     „  CO  =  1-251       „     =28. 

1     „     „  C  vapour  =  1  072       „     =  12. 

Each  volume  of  C02  contains  -rr  of  its  weight  of  carbon,  or 
1-966  x  f\  =  0-536  grams  per  litre.  Similarly,  the  proportion 
of  carbon  in  carbonic  oxide  is  f  of  the  weight,  or  1-251  X  f  — 
0-536  grams  per  litre,  the  weight  of  carbon  vapour  being  1-072 
grams  per  litre. 

Thus  the  total  weight  of  carbon  is  C  =  0-536  (v  +  v')  -f 
1-072  v"  where  v,  v'  and  v"  are  the  volumes  of  C02,  CO,  and 
carbon  vapour  in  litres  per  each  cubic  metre  or  per  1,000  volumes 
of  flue  gas. 

For  British  units  the  formula  becomes  C  =0-0335  (v  +  v') 
+  0-06693  v"  where  v,  v'  and  v"  are  the  volumes  in  cubic  feet 
per  thousand  feet  of  flue  gas. 

Kent's  formula  for  the  weight  of  dry  gas  per  pound  of  carbon 
is  — 

_11,  C02  +  80+7  (0+N) 
3  (C02  +  CO) 

Having  found  this  weight  of  dry  gas  from  the  analysis  of  the 
furnace  gases,  there  must  be  added  the  proportion  necessary 
for  the  steam  produced.  This  will  measure  9  by  weight  for 
each  unit  weight  of  hydrogen,  and,  the  density  of  steam  being  9, 
the  relative  volume  may  be  found,  or  it  may  be  taken  from  the 
above  table. 

By  formula  the  total  volume  of  gases  thus  becomes. 

C 

= 


0-536  (v+v')+  l-072v"  '  > 

where  H  is  the  percentage  of  hydrogen  in  the  fuel,  and  A  is  the 
combined  volume  of  nitrogen  and  excess  of  air. 

In  analysing  a  furnace  gas  there  are  two  main  methods. 
One  is  to  take  frequent  samples  rapidly  in  a  bottle  and  analyse 
this  by  the  Orsat  apparatus  :  the  other  is  to  take  a  sample, 
known  as  a  long  sample,  by  means  of  a  modification  of  the 
Sprengel  pump,  the  time  of  filling  the  sample  bottle  being 
extended  to  any  duration  wished,  even  several  hours.  The 


236         LIQUID  FUEL  AND  ITS   APPARATUS 

analysis  of  this  long  sample  gives  the  average  furnace  per- 
formance over  the  whole  time.  Short  samples  may  be  taken 
and  analysed  throughout  the  period  of  taking  the  long 
sample. 

For  these  analyses  the  Orsat  apparatus  may  be  employed 
as  most  convenient.  A  description  of  this  will  be  found  in  the 
author's  work  on  Liquid  Fuel  and  its  Combustion  and  in  manuals 
on  gas  analysis.  There  are  numerous  instruments  devised 
automatically  to  analyse  flue  gases  so  far  as  their  contents  of  C02 
is  concerned.  The  Arndt  apparatus  keeps  a  continuous  record 
of  the  density  of  the  gases  whence  the  percentage  of  C02  is 
shown  by  a  pointer,  and  it  may  be  arranged  to  show  a 
continuous  record.  The  Ados  apparatus  actually  analyses 
small  samples  of  the  gas  every  few  minutes,  and  records  this  on 
a  paper  band.  The  apparatus  of  Simmance  and  Abady  does 
the  same  thing  in  a  very  simple  manner.  Descriptions  of  the 
working  of  these  instruments  can  be  had  from  the  makers. 


Calorimeters. 

While  the  calorific  value  of  a  fuel  may  be  calculated  approxi- 
mately by  Dulong's  and  other  similar  formulae,  experiment 
must  be  resorted  to  for  more  exact  determinations.  For 
this  purpose  a  sample  of  fuel  must  be  actually  burned  in  a  very 
complete  manner  and  the  heat  must  be  measured  which  is 
given  off. 

Essentially  all  calorimeters  consist  of  a  vessel  in  which 
a  small  sample  of  the  fuel  to  be  tested  is  burned  by  a  stream 
of  oxygen.  The  whole  of  the  heat  produced  is  absorbed  by 
water  contained  in  an  enclosing  case  and  the  calorific  power 
is  calculated  from  the  rise  of  temperature  of  the  known 
weight  of  water  and  of  the  metal  of  the  instrument.  Various 
corrections  have  to  be  made  and  accurate  results  are  only  to 
be  obtained  with  great  care.  But  if  a  number  of  samples  are 
tested  under  similar  conditions,  their  comparative  values 
may  be  approximately  determined  without  going  to  the 
trouble  of  making  corrections  which  will  affect  all  samples 
alike. 

Descriptions  of  calorimeters  and  their  method  of  use  may  be 
found  in  the  Author's  book  on  Liquid  Fuel  and  its  Combustion, 
and  in  other  works  on  fuel. 

The  following  table  gives  the  calorific  power  of  a  few  oiLs 
and  tars. 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  237 


CALOBIMETBIC  VALUES  BY  BEKTHELOT  MAHLER  CALORIMETER 
ELEMENTARY  ANALYSIS. 


Character  of  Combustible. 

Carbon. 

Hydro- 
gen. 

Oxygen. 

Nitrogen. 

Calorific 
Value. 

Heavy  oil   from  American 

Cals. 

petroleum       

86-894 

13-107 

— 

— 

10,912-7 

Refined  American  petroleum 

85-491 

14-216 

— 

0-203 

11,045-7 

Treble     refined    American 

petroleum       .... 

80-583 

15-101 

— 

4-316 

11,086 

Crude  American  oil 

83-012 

13-389 

— 

3-099 

11,094-1 

Heavy  Baku  oil 

86-700 

12-944 

— 

— 

11,804-6 

Novorossisk        petroleum, 

Caucasian       

84-906 

11-636 

— 

9-458 

10,328 

Tar  from  hydraulic  main    . 

89-910 

4-945 

5-145 

— 

8-9428 

Tar  from  cooler 

87-222 

5-499 

6-279 

— 

8-8310 

Tar  from  condenser 

85-183 

5-599 

9-218 

— 

8-8384 

With  oil  fuel  alone  the  question  of  draught  is  of  compara- 
tively small  importance,  for  the  grate  and  its  load  of  fuel  form 
the  chief  resistance  to  draught  when  solid  fuels  are  used. 

The  draught  due  to  a  chimney  arises  from  the  differ- 
ence of  pressure  of  two  columns  of  gas  of  the  height  between 
the  grate  surface  and  the  chimney-top.  The  column  inside  the 
chimney  is  hot  because  of  the  furnace  through  which  it  has 
passed.  That  outside  the  chimney  has  the  temperature  of 
the  outer  atmosphere.  At  a  temperature  of  300°C.  (572°F.) 
the  inner  column  is  just  about  double  the  absolute  temperature 
of  the  outer  column,  so  that  the  relative  density  is  one-half. 

The  velocity  of  flow  of  a  gas  under  any  head  is  v  =.  \/2g  h> 
where  v  is  the  velocity  in  feet  per  second,  h  is  the  head  in  feet, 
and  2g  =  644  or  gravity  X  2.  Gravity  =  322. 

Expressed  in  metres  values  of  v  and  h  we  have  v  =  \/2  g  h, 
where  g  =9-81. 

Assuming  that  at  ordinary  temperatures  13  cubic  feet  of  air 
weigh  one  pound,  the  atmospheric  pressure  of  2,115  pounds  per 
square  foot  represents  a  column  27,495  feet  in  height,  which 
would  flow  into  a  vacuum  at  a  velocity  of  approximately 
8V27,495  =  1,321  feet  per  second. 

The  pressure  to  produce  draught,  however,  is  only  measured 
by  inches  of  water  pressure.  If  a  chimney  has  an  internal 
absolute  temperature  double  that  of  the  external  atmosphere, 
it  will  contain  only  one  pound  of  gas  for  each  26  feet  of  a 
column  of  gas  1  foot  square,  or,  what  is  the  same  thing,  the 
external  column  is  half-balanced  only.  Thus  if  H  be  the  height 
of  the  chimney,  H  -i-  (2  x  13)  will  give  the  pressure  per  square 
foot,  producing  draught.  Thus  a  chimney  of  104  feet  will 


238 


LIQUID  FUEL  AND   ITS  APPARATUS 


give  an  acting  pressure  of  4  pounds.  As  1  inch  of  water  gives 
a  pressure  of  0  036  pounds  per  square  inch,  the  draught  pressure 
of  the  above  chimney  would  be  — 


=°'7716  i 


144  X-  036 

Having  found  the  pressure,  the  air  column  equivalent  to 
this  must  be  found.  Water  weighs  624  pounds  per  cubic  foot. 
Air  weighs  0-077  pounds,  whence  the  equivalent  air  column,  in 
feet  per  inch  of  water  column  will  be  found. 

624 
12  X  0-077  = 

The  velocity  of  flow  is  then  8  A/67  H  or  fully  64  VH  where  H 
is  the"pressure  in  inches  shown  by  the  actual  water  gauge.  In 
coal-fired  furnaces  the  reading  of  the  draught  gauge  is  much 
greater  at  the  chimney  base  than  in  the  flues,  for  the  friction  of 
the  flues  exerts  considerable  resistance.  The  simplest  form  of 
water  gauge  is  a  bent  glass  tube  of  U  form,  one  end  being  open 
to  the  atmosphere,  the  other  connected  by  a  piece  of  india- 
rubber  tubing  to  a  piece  of  pipe  which  enters  the  flues  at  the 
point  where  the  draught  intensity  is  sought. 

It  is  convenient  to  remember  that  where  the  velocity  of 
flow  due  to  head  in  feet  is  v=V2gh,  that  due  to  a  pressure 
as  shown  in  inches  of  water  is  almost  exactly  z=2gVH.  All 
these  figures  can  only  be  approximate,  because  they  will 
vary  with  the  temperature.  They  are  sufficiently  accurate 
to  base  designs  upon  in  respect  of  providing  sufficient  openings 
for  air  to  burn  the  oil. 

The  following  table  of  velocities  of  air  for  a  few  pressures  in 
inches  of  water  will  be  useful  — 


Pressure  in 
inches  of  water. 

Velocity  of  air  in  feet. 

Per  second. 

Per  minute. 

0-1 

20-7 

1,243 

0-2 

29-3 

1,758 

0-3 

35-8 

2,150 

0-4 

41-4 

2,485 

0-5 

46-3 

2,778 

0-6 

50-7 

3,043 

0-7 

54-8 

3,287 

0-8 

58-5 

3,513 

0-9 

62-1 

3,726 

1-0 

65-4 

3,927 

2-0 

92-4 

5,547 

STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  239 

An  ordinary  U  gauge  is  not  capable  of  being  finely  read. 
It  possesses  a  capillarity  which  is  difficult  to  allow  for  and  will 
not  serve  for  accurate  work.  A  better  gauge  consists  of  a 
glass-fronted  box  in  two  divisions  partly  filled  with  water. 
A  hook  gauge,  reading  on  a  scale,  permits  very  accurate  mea- 
surement. Descriptions  of  this  and  other  gauges  may  be 
found  in  the  Author's  larger  work  and  in  other  works  on  solid 
fuels.  But  since  with  solid  fuels  the  greater  part  of  the  draught 
is  used  in  overcoming  grate  resistance  the  question  is  of  com- 
paratively small  importance  where  liquid  fuel  alone  is  em- 
ployed, since  unencumbered  furnaces  and  flues  with  a  short 
chimney  appear  capable  of  carrying  away  all  the  gases  from 
liquid  fuel. 

In  coal  firing,  about  three-fourths  of  the  draught  is  swal- 
lowed up  by  grate  and  fuel  friction.  With  oil  firing  alone 
and  no  grate  friction  there  is  usually  ample  velocity  of  the  in- 
flowing air.  The  chimney,  in  fact,  ceases  to  possess  so  much 
importance,  but  must  be  large  enough  in  area  to  carry  off  the 
waste  gases. 

The  weight  of  a  cubic  foot  of  air  at  0°C.  =  32°F.  being 
0-08  lb.5  that  at  any  other  temperature  will  be 

0-08  x  273 
973  -L  /°     wnere  »    1S  expressed  in  degrees  Centigrade 

,  0-08  x  491 
and  -  0  where  t  is  in  degrees  Fahrenheit. 

By  these  formulae  may  be  calculated  the  weight  of  air  inside 
and  outside  a  chimney.  The  difference  of  the  two  is  the 
pressure  to  produce  draught  per  foot  of  chimney  height. 

Calling  D  and  d  the  greater  and  less  densities  the  equivalent 
height  of  a  column  for  any  chimney  of  height  =  h  ft.  will  be 
L  =  h  (2=?)  and  the  velocity  of  flow  per  second  will  be 

v  =  V%  g  L  where  L  is  the  equivalent  column  in  feet. 

In  all  the  foregoing  the  specific  gravity  of  furnace  gas  is 
assumed  equal  to  that  of  air  of  the  same  temperature,  the 
steam  balancing  the  carbonic  acid  more  or  less  closely. 

Seeing  that  draught  is  of  less  importance  with  liquid  fuel, 
it  is  permissible  to  reduce  the  furnace  products  to  a  lower 
temperature  if  facilities  can  be  had  for  doing  this.  The  smaller 
excess  of  air  with  which  perfect  combustion  can  be  secured  is 
a  factor  in  rendering  more  efficient  the  heating  surfaces  of  the 
boiler,  and  reduced  flue  gas  temperatures  are  a  natural  con- 
seqence  of  liquid  fuel. 

A  chimney  must  be  large  enough  to  pass  all  the  products  of 


240          LIQUID  FUEL  AND   ITS  APPARATUS 

a  furnace  at  a  certain  given  velocity  of  flow.  The  calculation 
of  chimney  area  is  thus  simple.  Assuming  the  velocity  of  flow 
of  gas  to  be  30  feet  per  second,  it  is  simply  necessary  to  divide 
the  volume  of  gas  produced  per  second  by  30.  The  result  is 
the  area  in  square  feet  of  the  chimney.  To  find  the  volume 
of  gas  produced  per  second,  the  fuel  consumption  per  second 
is  first  found  as  follows  in  pounds  — 

W  X  2  240 
P  =  fj  ------  'oV      wnere   W  *s  the  daily  consumption  in  tons 


and  H  the  daily  hours.  Then  P  x  20  =  pounds  of  gas  =  G. 
At  ordinary  temperatures  one  pound  of  gas  measures  13  cubic  ' 
feet  very  closely.  At  the  chimney  temperature  it  will  measure 
20  to  25  feet.  Let  22  be  assumed  :  then  G  x  22  4-  30  will 
give  the  area  of  the  chimney  inside  =A.  The  chimney  will 
measure,  if  square,  VA,  on  each  side,  or,  if  round,  its  diameter 
will  be  D  =  1-128  VZ. 

With  oil  a  very  small  draught  will  draw  in  enough  air  for 
perfect  combustion,  and  it  is  usually  necessary  rather  to  check 
the  flow  of  the  gases  through  the  flues,  only  sufficient'  draught 
being  required  to  remove  the  products  of  combustion  as  formed. 
Chimneys  of  small  altitude  will  do  this,  for  they  do  not  require 
to  overcome  any  grate  or  fuel-bed  resistance.  In  locomotives, 
tor  example,  the  steam  blast  may  be  considerably  reduced, 
and  on  the  Great  Eastern  Railway  of  England  the  MacAllan 
variable  blast-pipe  is  enlarged  from  5  inches  with  coal  to  5J 
inches  diameter  with  oil  to  the  reduction  of  the  back  pressure 
on  the  pistons  and  economy  of  steam  in  consequence.  In 
foreign  locomotive  practice  it  is  usual  to  employ  caps  over  the 
chimney-top  in  order  to  save  the  loss  of  heat  when  running 
down  grade  or  standing  idle.  Mr.  Urquhart  continued  to  use 
this  cap  with  his  oil-fired  engines,  and  though  it  presents  an 
odd  appearance  to  English  eyes,  the  cap  has  advantages. 
Applied  to  stationary  work  it  is  represented  ordinarily  by  a 
damper  at  the  chimney-base,  and  is  thus  recognized  as  good, 
but  it  is  not  used  in  locomotive  work.  It  affords  a  ready 
means  of  regulating  the  fires,  and  cannot  quite  be  replaced 
by  the  ash-pit  damper,  which  is  heavier  to  work  and  is  by  no 
means  always  so  tight-shutting  as  it  should  be. 

A  very  usual  remedy  for  a  bad  draught  in  coal-fired  furnaces 
is  a  steam  jet.  In  oil-firing  this  aid  to  draught  is  present  in 
the  atomizer,  which  really  replaces  the  need  for  a  certain 
chimney  or  fan  effect.  The  area  of  chimneys  must  not  be 
calculated  from  the  horse-power  to  be  developed.  The  actual 


STORAGE  AND  DISTRIBUTION  OF  LIQUID  FUEL  241 

fuel  consumption  should  be  worked  from.  The  fuel  per  horse- 
power hour  will  vary  according  to  the  load-factor  and  other 
conditions,  and  large  stations  will  use  less  fuel  per  horse-power 
hour  than  will  small  stations  with  smaller  load-factors.  Each 
case  must  stand  by  itself.  A  very  small  draught  will  give  a 
velocity  of  30  feet  per  second.  Ordinary  rules  for  chimneys 
provide  for  areas  that  will  reduce  the  velocity  of  flow  to  much 
less  than  the  foregoing  30  feet  per  second,  but  it  is  doubtful  if 
such  large  areas  are  necessary  with  liquid  fuel,  and  it  is  certain 
that  a  chimney  hitherto  used  for  solid  fuel  will  serve  well  when 
a  change  is  made  to  liquid  fuel.  Experience  so  far  is  lacking 
on  the  question  of  chimney  practice  for  liquid  fuel  work,  but 
the  subject  may  be  approached  from  the  standpoint  above, 
viz.,  that  with  liquid  fuel  not  only  is  the  resistance  of  the  fuel 
on  the  grate  eliminated  but  there  is  added  a  propelling  force 
in  the  atomizer  which,  if  applied  to  a  poor  draught  hi  a  coal- 
burning  furnace,  would  render  such  draught  good  and  sufficient. 
Bearing  these  points  in  mind,  the  ordinary  treatises  on  draught 
may  be  studied  with  advantage  as  regards  the  effect  of  height 
upon  velocity  of  flow.  But  the  ordinary  rules  otherwise  have 
little  application  to  liquid  fuel  conditions. 


CHAPTER    XVII 

COMPRESSED   AIR   AND   AIR   COMPRESSORS 

THE  use  of  air  as  the  atomizing  agent  has  been  delayed 
because  steam  is  more  readily  obtained,  and  where 
the  loss  of  fresh  water  in  the  form  of  steam  is  not  a  serious 
matter,  it  is  claimed  that  steam  is  a  cheaper  agent  than  air, 
which  must  be  compressed  by  steam  power  to  begin  with. 
But  steam  is  not  a  supporter  of  combustion,  and  air  is  ;  and 
there  is  a  tendency  to-day  to  employ  air  where  possible, 
and  to  use  it  hot.  Air  being  so  nearly  a  perfect  gas,  the  whole 
work  of  compressing  it  is  practically  converted  into  heat, 
and  the  temperature  of  the  compressed  air  is  raised.  In  the 
compression  of  air  to  60  pounds  per  square  inch  or  more  it  is 
usual  to  compress  in  two  stages,  cooling  both  cylinders  by  means 
of  a  water  jacket,  and  cooling  the  air  between  the  two  stages  by 
means  of  a  tubular  receiver  or  a  sufficient  area  of  exposed 
tubes.  But  in  fuel  atomizing  a  pressure  of  15  pounds  to  20 
by  gauge  is  usually  held  to  be  ample,  and  generally  it  is  not 
necessary  to  use  air  at  the  same  high  pressure  as  steam.  Air  is 
much  heavier  than  steam,  and  more  energetic  per  unit  volume. 
But  this  does  not  apply  to  air  which  must  of  necessity  be  intro- 
duced into  the  furnace  and  is  required  for  the  proper  combustion 
of  the  fuel.  Air  compressors  are  somewhat  awkward  machines, 
and,  especially  on  shipboard,  are  not  easily  housed.  For  oil 
atomizing  it  is  not  necessary  to  employ  a  two-stage  com- 
pressor. The  heat  of  compression  is  not  great  for  the  first 
moderate  stage  of  15  to  30  pounds,  and  after  the  air  leaves  the 
compressor  it  should  be  heated  on  its  way  to  the  atomizer. 
This  is  usually  effected  by  means  of  pipes  in  the  flues  of  the 
stationary  boiler  or  in  the  smoke-box  of  the  locomotive. 

The  curve  of  isothermal  compression  of  a  perfect  gas  is  the 
hyperbola,  the  equation  to  the  curve  being  such  that  Pv  = 
constant. 

Thus  two  cubic  feet  at  40  pounds  absolute  pressure  become 
one  cubic  foot  at  80  pounds,  but  the  temperature  remains 
constant. 

242 


COMPRESSED  AIR  AND  AIR   COMPRESSORS      243 

When  air  is  compressed  adiabatically,  or  without  loss  or 
gain  of  heat,  its  curve  has  the  equation — 

P 

P 

P  being  the  pressure  corresponding  to  the  small  volume  v, 
and  V  the  volume  at  small  pressure  p. 
Assuming  the  volume  v  =  I  we  have — 

p  V1-403 

_____       or  P  =  #  V1'408 
p       1 

Thus  air  at  pressure  p  =15  is  compressed  to  P  =  90. 

p 
Then  —  =  6  and  the  relative  volumes  before  and  after  com- 

P 

pression  are  for  v  =  1. 

yi-403        p 


The  log.  of  6  is  0-77815 

and  0-77815  4-  1408  =  0-55266,  which  is  the  log.  of  3-57  =  V. 

Thus  in  place  of  an  original  6  vols.  of  air,  only  3-57  will  be 
needed  to  give  a  final  volume  of  1,  owing  to  the  increased 
volume  due  to  temperature  rise.  For  a  moderate  compression 
of  2  only  we  shall  have  V  1-408  =  2.  The  log.  of  2  is  0-30103 
and  030103-^  1408  =  0-2138,  which  is  the  log.  of  1-636, 
this  being  the  number  of  compressions  necessary  to  give  a 
double  pressure  instead  of  two  compressions,  had  the  tempera- 
ture been  kept  down  or  V  =  1-636. 

The  heat  generated  in  compressing  a  gas  from  a  pressure  of  p 
to  a  pressure  of  pL  is  — 


»> 

where,  7,  according  to  Rankine,  is  1-408;  p  and  p±  are  the 
initial  and  final  pressures  in  atmospheres  and  H  =  foot-pounds, 
T0  being  the  absolute  temperature  whence  the  heat  units  per 
pound  of  air  compressed  will  be  H  -f-  772,  and  the  temperature 

TT 

0-237  being  the  specific  heat  of  air. 


The  work  done  in  compressing  and  delivering  one  pound  of 
air  is  thus,  in  foot-pounds  — 


244 


LIQUID  FUEL  AND  ITS   APPARATUS 


Fig.   63. 


whence  can  be  found  the  power  required  for  compression.  The 
efficiency  overall  from  motor  switch-board  should  not  be  taken 
above  70  per  cent,  when 
designing  a  motor  for  the 
purpose.  The  overall 
efficiency  of  a  first-class 
air  compressor  is  said  to 
exceed  70  per  cent,  with 
its  electric  motor,  but  or- 
dinary compressors  cannot 
be  calculated  above  50  per 
cent. 

Since  free  air  weighs 
one  pound  for  each  cubic 
13  feet  at  ordinary  tem- 
peratures, the  size  of  com- 
pressor required  for  any  a 
weight  of  air  is  easily 
calculated  from  the  speed 
and  piston  displacement. 

In  a  water-cooled  compressor  the  index  of  the  curve  of  com- 
pression of  a  good  compressor  may  be  safely  taken  at  7  =  1  -2 
in  place  of  1-408,  as  in  adiabatic  compression. 

The  subject  of  air  compression  is  one  of  such  importance  in 
respect  of  liquid  fuel  combustion  as  to  justify  full  explanation 
of  the  peculiar  action  of  a  perfect  gas. 

Air  is  so  nearly  a  perfect  gas  that  there  is  very  little  internal 

work  done  upon  it  when 
it  is  compressed.  All 
the  work  appears  as 
heat.  In  Fig.  63  this 
action  is  shown  dia- 
gramatically.  A  volume 
of  air  a  b  at  the  pres- 
sure b  n  of  one  atmo- 
sphere, if  compressed 
to  several  atmospheres 
so  slowly  that  it  loses  all 
the  heat  of  compression 
at  once,  will  occupy  a 
volume  c  d  at  the  pres- 
sure a  c. 

The  area  a  b  n  i  will 
in  other  words,  the 


Fig.  64. 

be  exactly  equal  to  the  area  a  c  d  m  ; 


product  of  pressure  and  volume  is  constant. 


COMPRESSED  AIR  AND  AIR  COMPRESSORS      245 

If  compressed  quickly,  without  loss  of  heat,  the  curve  n  k 
will  be  described  and  the  volume  of  the  compressed  air  will  be 
c  k.  The  rectangle  d  a  is  equal  to  the  rectangle  a  n  for  d  and  n 
are  points  in  the  isothermal  curve  n  d.  Consequently  the 
rectangles  d  i  and  m  n  must  be  equal  and  n  k  c  i  is  equal  to 
m  b  n  k  d,  or,  in  words,  the  mechanical  work  of  adiabatic  com- 
pression is  equal  to  the  work  done  in  compression  and  delivery. 

If,  in  place  of  single-stage  compression,  the  double-stage 
system  be  adopted,  the  principle  of  intermediate  cooling  can 
be  employed.  Thus,  in  Fig.  64  compression  is  first  carried  to 
the  point  o  ;  the  compressed  air  is  cooled  in  the  receiver  to 
the  point  j,  and  arrives  at  the  ultimate  pressure  a  c  with  a 
volume  very  little  greater  than  c  d.  The  diagram  is  less  in 
area  than  Fig.  63  by  the  area  j  o  k  q,  and  this  represents  energy 
economized  during  compression. 

These  same  principles  and  arguments  may  be  applied  to  the 
use  of  air  in  two  stages  in  place  of  one.  Thus,  the  compressed 
air  may  be  made  to  run  a  pump  the  exhaust  from  which  is 
carried  to  a  hoisting  engine  or  other  motor. 

When  compressing  air  the  heat  of  compression  is  dissipated 
to  the  atmosphere,  and  when  the  air  is  used  again  in  a  two- 
stage  expansion  it  is  reheated  between  the  stages  by  absorption 
of  heat  from  the  atmosphere,  which  thus  serves  the  part  of  a 
general  equalizer,  absorbing  heat  from  compressed  air  and 
giving  it  out  again  to  expanding  air. 

It  is  stated  by  Lieutenant  Winchell  that  tests  made  on  vari- 
ous atomizers  show  that  each  pound  of  water  evaporated 
from  and  at  212°F.  requires  one  cubic  foot  of  free  air  compressed 
to  20  Ib.  gauge  pressure  =35  Ib.  absolute.  Assuming  that 
1  Ib.  of  oil  will  evaporate  13lb.  of  water,  and  that  13  cubic  feet 
of  air  are  equivalent  to  1  Ib.,  the  figures  represent  1  Ib.  of  air  to 
atomize  1  Ib.  of  oil.  How  much  power,  then,  will  be  required 
to  atomize  the  fuel  for  1,000  h.p.,  using,  say,  16  Ib.  of  steam 
per  h.p.  hour,  with  an  evaporation,  say,  of  14  Ib.  per  pound  of 
oil?  Here  1,000  x  |J  =1,143  Ib.  of  oil  per  hour,  or  1,143 
Ib.  of  air.  This  is  19  Ib.  of  air  per  minute,  to  compress  which, 
according  to  equation  (2)  adiabatically  from  a  temperature 
of  62°F.=  522°  absol.,  will  require  per  pound  of  air  — 


per  pound  of  air  compressed  to  20  Ib.  gauge  pressure  per  minute. 
At  70  per  cent,  efficiency,  this  becomes  1-2  h.p.  nearly,  or  a 


246          LIQUID  FUEL  AND   ITS  APPARATUS 

total  of  22-8  h.p.  for  the  total  engine  power  of  1,000,  which  is 
less  than  2J  per  cent,  of  the  total  power  ;  whereas  steam  ato- 
mizing requires  3  to  5  per  cent,  of  the  total  power  of  a  boiler. 
The  citation  of  the  air  per  pound  of  evaporation  is  hardly 
a  correct  method,  but  not  much  is  yet  known  of  this  part  of 
the  subject,  and  meantime  one  pound  of  air,  or  13  cubic  feet 
of  free  air,  should  be  provided  per  pound  of  oil ;  and  probably 
with  the  cooling  effect  allowed  for,  one  brake  horse-power  will 
compress  one  pound  of  air  to  20  pounds  gauge  pressure.  The 
figures  thus  confirm  M.  Bertin's  orginal  ideas,  as  given  below. 

The  above  calculation  is  for  adiabatic  compression. 

Per  kilogram  of  air  per  minute  the  power  expended  in  air 
compression  will  be  nearly  50  h.p. 

To  spray  one  kilo,  of  oil  requires  28-6  cubic  feet  of  free  air, 
or  812-0  litres.  As  it.  is  usual  to  order  air  compressors  by  their 
capacity  in  cubic  feet  of  free  air,  the  amount  of  one  unit  weight 
per  unit  of  oil  works  out  at  13  cubic  feet  per  h.p.  hour,  more  or 
less,  according  to  the  efficiency  of  steam  engine  and  boilers,  or 
from  20  to  25  cubic  feet  per  minute  per  100  h.p.  From  this 
the  size  of  air  compressor  can  be  calculated. 

Thus  an  air  compressor  will  have,  say,  a  total  useful  piston 
stroke  equal  to  3  feet  per  revolution.  At  240  revolutions  per 
minute,  this  represents  720  linear  feet.  With  10  inch  dia- 
meter pistons  the  capacity  is  thus  about  390  cubic  feet  per 
minute,  less,  say,  10  per  cent,  for  slip  or  350  cubic  feet,  which 
should  supply  about  1,400  to  1,700  h.p.  of  burners  in  a  fairly 
economical  plant.  An  allowance  of  ten  per  cent,  for  slip  is 
enough  in  these  compressors  for  80  pounds  compression,  and  is 
therefore  more  than  ample  for  ordinary  low  pressure  work. 

The  compressor  lends  itself  readily  to  electric  driving.  Auto- 
matic regulating  devices  are  fitted  to  maintain  the  air  pressure 
constant  in  the  case  of  electric  driving  by  rheostatic  control 
actuated  by  the  air  receiver  pressure. 

M.  Bertin,  of  the  French  Navy,  states  that  a  good  compressor 
will  not  use  half  the  steam  that  is  used  where  steam  atomizing 
is  employed,  for  steam  will  compress  more  than  its  own  weight 
of  air  up  to  its  own  pressure  ;  and  it  can  hardly  be  doubted  that 
for  naval  and  marine  purposes  generally  the  use  of  air  for 
atomizing  must  eventually  become  general. 

In  the  foregoing  calculations  the  compression  of  the  air  has 
been  assumed  to  be  adiabatic.  This  is  not  strictly  correct 
even  in  uncooled  cylinders,  and  some  distance  from  correct- 
ness in  cooled  cylinders,  but  any  error  is  on  the  right  side,  and 
it  is  better  to  proportion  the  air  compressors  on  an  adiabatic 
basis,  so  that  there  may  be  a  fair  allowance  of  power. 


COMPRESSED  AIR  AND  AIR  COMPRESSORS      247 


As  already  stated,  where  the  index  of  the  adiabatic  curve  is 
y  =  1 4,  and  that  of  the  isothermal  curve  is  y  =  1  -0,  practical 
work  may  be  done  at  values  of  y  =  1-2.  Expanding  air  be- 
comes so  very  cold  that  between  the  compressor  and  the  ato- 
mizer air  should  be  heated  as  hot  as  possible,  in  order  to 
counteract  the  chilling  effect. 

For  compound  compressors,  which  so  far  hardly  come  into 
the  sphere  of  liquid  fuel  work,  the  power  required  to  compress 
up  to  an  absolute  pressure  of  2,  4  or  6  atmospheres  is  as  follows, 
compared  with  adiabatic  compression  in  a  single-stage  machine — 


Pressure  in  Atmospheres. 
Absolute. 

Ratio  of  Power. 
W2  ;  Wi. 

Probable  Ratio 
in  practice. 

2 
4 
6 

•951 
•901 
•871 

•975 
•950 
•935 

Even  in  single-stage  compression  the  actual  power  required 
in  a  cooled  machine  will  probably  be  about  midway  between 
the  figures  for  adiabatic  and  two-stage  intercooled  work. 
See  column  3  above. 

As  explained  elsewhere,  the  economy  of  cooling  is  doubtful  ; 
though  if  there  are  suitable  means  of  heating  the  air,  it  is  ex- 
pensive to  heat  it  by  expending  power  upon  it. 

In  the  following  table  is  given  the  horse-power  necessary  to 
compress  one  pound  of  air  to  2,  4  and  6  atmospheres  pressure 
absolute  from  the  ordinary  temperature  of  60°F.  —  15-5°C. 
The  figures  are  for  adiabatic  compression  of  one  pound  per 
minute — 


Absolute 
Atmospheres. 

Horse  Power. 

Actual  h.p.  of 
driving  motor. 

Gauge  Pressure. 

2 

4 
6 

0-645 
1-433 
1-972 

0-860 
1-911 
2-629 

14-7  Ib. 
44-1    „ 
73-5   „ 

The  difference  between  adiabatic  and  isothermal  compression 
is  of  no  serious  account  up  to  30  Ib.,  or  even  to  45  Ib.  The 
volumetric  efficiencies  of  good  compressors  at  these  low  pres- 
sures may  be  safely  taken  at  90  per  cent,  of  the  piston  displace- 
ment. The  efficiency  of  the  machine  being,  say,  75  per  cent, 
overall  from  engine  to  compressor,  the  indicated  horse-power 
actually  required  will  be  found  by  adding  one-third  to  the 
figures  in  column  2,  whence  is  found  column  3. 

Apparently,  therefore,  air  for  atomizing  may  be  compressed 
by  one  horse-power  to  the  extent  of  about  60  pounds  weight  per 


248          LIQUID  FUEL  AND  ITS  APPARATUS 

hour.  Now,  one  horse-power  in  a  good  steam  engine  will  con- 
sume, say,  16  Ib.  of  steam  per  hour,  or,  say,  20  Ib.  per  electrical 
horse-power  hour,  so  that  under  favourable  circumstances  1  Ib. 
of  steam  should  compress  3  Ib.  of  air  ;  and  air  should,  appar- 
ently, be  the  better  agent  to  employ,  quite  apart  from  the 
advantage  at  sea  of  not  wasting  fresh  water.  Further  experi- 
ment is,  however,  required  to  afford  reliable  and  fuller  figures 
before  a  hard  and  fast  ruling  can  be  even  attempted.  The 
Author's  own  opinion  is  in  favour  of  air  heated  to  a  considerable 
temperature  and  more  or  less  charged  with  moisture  to  assist 
in  preventing  fouling  of  the  atomizers. 


Flow  of  Air. 

Mr.  D.  K.  Clarke  gives  the  velocity  of  air  flowing  from  any 
pressure  P  into  any  other  lower  pressure  of  not  more  than  f 
of  P  as  880  feet  per  second. 

Actual  experiments  upon  orifices  having  a  length  greater  than 
their  diameter  give  about  750  feet  per  second. 

The  following  results  were  obtained — 

50  Ib.  gauge  pressure  blowing  through  f"  nozzle  to  atmosphere  —775  ft. 
30  |"  =725 


45 
16 
25 

7 
25 


r 
r 


=  778 
=  725 
=  748 
=  898 
=  675 


The  last  two  results  were  doubtful. 

It  will  be  safe  to  count  upon  a  velocity  of  750  feet  in  making 
calculations  as  to  the  weight  of  air  which  will  pass  an  orifice. 
The  above  velocities  are  calculated,  of  course,  on  the  air  at  the 
higher  pressure.  The  weight  of  air  is  proportional  to  the  ab- 
solute pressure,  twice  as  much  air  escaping  at  35  Ib.  gauge  pres- 
sure as  at  10  Ib.,  that  is  to  say  at  50  Ib.,  and  25  Ib.  absolute. 

On  the  relative  economy  of  air  or  steam  for  atomizing,  Pro- 
fessor WiUiston  says  unquestionably  that  air  at  2  to  5  or  even  10 
pounds  per  square  inch  is  more  economical  than  steam,  so 
far  as  the  spraying  is  concerned.  At  higher  pressures  there 
is  a  doubt  as  to  economy,  for  the  cost  of  compression  increases 
rapidly  with  the  pressure,  and  the  atomizing  capacity  of  the 
air  does  not  increase  at  the  same  rate.  Thus  in  the  U.S.  Navy 
tests  the  most  economical  results  were  found  with  air  pressures 
of  only  one  or  two  pounds.  All  atomizers  will  not  work  at  this 
pressure.  At  these  low  pressures,  however,  less  than  two  per 


COMPKESSED  AIR  AND  AIR  COMPRESSORS      249 

cent,  of  the  steam  generated  would  compress  the  air.  At  an 
air  pressure  of  four  or  five  pounds,  four  per  cent,  of  the  total 
steam  was  required  to  compress  the  air.  Obviously,  where 
atomizers  will  act  satisfactorily,  it  will  be  advantageous  to  use 
much  air  at  a  low  pressure  in  order  that  the  combustion  may  be 
improved,  for  air  must  enter  the  furnace,  and  in  air  atomization 
there  is  not  the  risk  of  fire  extinguishment  that  there  is  with 
steam. 


CHAPTER    XVIII 

THE   ATOMIZING   OF  LIQUID   FUEL 

SINCE  liquid  fuel  of  the  heavy  varieties  cannot  be  burned 
except  by  atomizing,  the  burner,  injector,  sprayer  or 
atomizer,  as  it  is  variously  termed,  is  an  important  detail. 

Its  object  is  the  pulverizing  of  the  liquid,  so  that,  mixed  with 
air  in  the  act  of  pulverization,  and  supplied  with  any  further 
amount  of  air  that  may  be  necessary,  the  liquid  atoms  may 
burn  like  vapour. 

The  spray  must  not  be  so  directed  than  an  intense  blow-pipe 
flame  impinges  severely  upon  any  small  area  of  furnace  plate. 
It  is  sought  to  fill  the  furnace  with  a  full  soft  voluminous  flame 
which  shall  envelop  its  whole  interior.  Given  a  sufficiently 
long  space  in  front  of  the  burner,  a  spray  directed  straight 
ahead  and  coning  out  would  doubtless  produce  a  satisfactory 
effect,  but  the  space  between  the  point  of  the  burner  and  that 
part  of  the  cone  of  flame  which  first  touched  the  furnace  plate 
would  be  of  little  use  as  heating  surface.  What  should  be 
aimed  at  is  such  a  burner  and  spray  device  as  will  produce  a 
certain  disrupture  and  outward  expanding  effect,  so  as  at  once 
to  spread  the  oil  to  a  considerable  extent  normally  to  the  axis 
of  the  burner  as  well  as  parallel ;  to  give  a  sort  of  balloon  effect, 
so  that,  in  a  locomotive  boiler  for  example,  there  shall  be 
flame  well  to  the  back  of  the  box  as  well  as  forward  under  the 
arch.  Various  forms  of  atomizers  will  be  found  illustrated  in 
this  or  earlier  chapters,  including — 

The  Holden  (Figs.  23,  24  and  25).  The  Billow  (Fig.  44). 

The  Baldwin  (Fig.  34).  The  Aerated  Fuel  Co.  (Fig.  67). 

The  Urquhart  (Fig.  42).  Kermode's    Burners    (Figs.    68, 

The  Hydroleum  Co.  (Fig.  71).  69). 

The  Swensson  (Fig.  73).  Orde's  (Fig.   15). 

The  Guyot  (Fig.  75).  Korting's  (Figs.  21,  21a). 

The  Rusden  and  Eeles  (Fig.  66).  The  Hoveler  (Fig.  65),  p.  287. 

The  Holden  Atomizer. 

The  Holden  Injector  (Figs.  23,  24,  25)  consists  of  a  gun-metal 
casing  with  oil,  air  and  steam  inlets.  Air  comes  in  at  the  back, 

250 


THE  ATOMIZING  OF  LIQUID  FUEL 


251 


preferably  hot,  and  is  delivered  at  the  point  where  the  oil 
escapes  to  the  inner  nozzle.  Steam  comes  between  the  oil  and 
air,  and  the  mixed  jet  escapes  forward  and  slightly  laterally  by 
two  orifices.  A  further  air  supply  is  directed  upon  the  spray  by 
a  ring  of  several  fine  jets  of  steam.  The  atomized  fuel  is  direc- 
ted along  the  plane  of  the  fire  when  the  fire-bars  are  retained, 
as  this  gives  the  best  action.  Mr.  Holden  does  not  confine 
himself  to  the  use  of  steam  as  an  atomizing  agent,  but  recognizes 
that  air  may  be  preferable  for  chemical  reasons.  Two  burners 
deal  with  about  six  pounds  of  oil  each  per  mile,  or,  say,  240 
pounds  her  hour. 


LU 

Fig.  66.     ATOMIZER.     RUSDEN-EELES. 

Eusden  and  Eeles. 

In  this  burner  Fig.  66),  steam  escapes  by  a  central  annular 
jet,  and  is  directed  outwards  on  a  fine  annular  jet  of  oil,  which 
is  heated  also  by  a  steam  jacket.  This  disposition  gives  a 
balloon  flame.  The  burner  is  largely  used  in  marine  work. 

The  Urquhart. 

This  (Fig.  42),  one  of  the  earliest  successful  atomizers, 
employs  central  steam,  external  air,  and  an  annular  oil  jet 
between  the  two,  the  expansion  of  the  steam  atomizing  the  oil 
into  the  air  and  mixing  the  two. 


252         LIQUID  FUEL  AND  ITS  APPARATUS 

The  Baldwin  (Fig.  34). 

The  burner  is  very  simple,  being  simply  a  broad  thin  jet  of 
steam  which  is  directed  upon  oil  escaping  from  a  parallel 
passage.  It  could  not  well  be  simpler,  but  it  is  claimed  to 
act  well,  and  there  appears  no  reason  to  doubt  this. 

The  Aerated  Fuel  Company's  Burner. 
This  is  of  the  central  air  jet  type,  as  shown  in  Fig.  67. 


Fig.   67.     ATOMIZER.     AERATED  FUEL  SYSTEM. 

The  Kermode  Burners. 

The  latest  type  of  Kermode  burner  is  the  pressure-jet  burner 
specially  designed  for  naval  and  other  vessels,  and  recommended 
for  use  with  forced  or  induced  draught.  The  burner  is  shown 
in  longitudinal  section  and  in  plan  respectively  in  Fig.  68. 
The  oil  enters  through  the  channel  A,  and  passes  between 
the  outer  wall  D  and  the  inner  cylinder  B,  which  abuts  against 


THE  ATOMIZING  OF  LIQUID  FUEL 


253 


the  cap-nut  E.  The  end  of  the  cylinder  B  is  an  exact  fit  in  D 
where  it  abuts  against  the  nut  E,  and  in  this  end  of  B  a  number 
of  grooves  are  cut  parallel  to  the  centre  line  of  the  burner, 
while  there  are  similar  grooves  in  the  end  of  the  part  B  at  right 
angles  to  the  axis  of  the  burner.  These  grooves  are  shown 
at  H,  and  they  are  tangential  to  the  cone  end  of  the  spindle 
C,  which  serves  to  contract,  or  enlarge,  the  opening  through 
the  cup-nut  E.  The  movement  of  C  is  indicated  on  the  gradu- 
ated wheel  F. 

The  oil  fuel  is  pulverized  by  being  forced  through  a  restricted 


Fig.  68.      ATOMIZER.     KERMODE'S  PRESSURE  SYSTEM. 

opening  with  a  rotary  motion,  which  is  given  to  it  by  the 
tangential  grooves  in  the  face  of  the  plug  B,  and  it  is  distributed 
in  the  form  of  a  cone  by  means  of  the  reaction  or  deflection 
which  is  set  up  by  the  oil  impinging  on  the  cone  end  of  the 
spindle  C,  the  pulverization  being  effected  by  means  of  the 
pressure  which  is  brought  to  bear  upon  the  oil  fuel  itself  by 
means  of  a  force-pump.  The  oil  is  heated  and  filtered.  The 
fixed  pointer  marked  G  serves  to  indicate  the  degree  to  which 
the  wheel  F  has  been  rotated,  to  increase  or  diminish  the 
opening  through  the  nut  E. 

Fig.  69  shows  a  section  of  the  latest  Kermode  hot-air  burner. 
In  this  burner  the  oil  is  partially  vaporized  and  sprayed  by  hot 
air  at  a  pressure  of  half  to  four  pounds,  the  industrial  furnace 
working  with  the  former  pressure  and  the  naval  boiler  calling 


254          LIQUID  FUEL  AND  ITS  APPARATUS 

for  3  to  4  Ib.  Oil  enters  at  A,  and  is  regulated  by  the 
wheel  E  and  the  valve  on  spindle  D.  Hot  air  enters  at  B 
and  C  and  the  long  helix  K  gives  a  rotary  motion  to  the  oil  and 
air  and  insures  that  none  of  the  oil  vapour  will  pass  through 
the  tube  untreated.  The  supply  of  air  can  be  regulated  at  two 
points  by  means  of  hand  wheels,  pinions,  and  racks  ;  one  pinion 
L  moves  the  internal  tube  over  the  oil-delivering  nozzle  F, 
and  regulates  the  air  which  enters  there.  The  second  pinion 
M  operates  the  outer  tube,  and  varies  the  amount  of  air 
escaping  around  the  mixed  jet  at  the  end  of  the  twisted  spindle 
K.  All  the  elements  of  the  combustion  are  under  complete 
control.  The  oil  as  it  trickles  from  the  nozzle  beyond  the  valve 
is  swept  forward  by  a  sharp  current  of  air  which  envelops  the 
nozzle  ;  this  current  can  be  regulated  with  great  exactitude. 
A  further  compressed  air  supply  is  given  where  combustion 


Fig.  69.     ATOMIZER.     KERMODES  HOT  AIR  SYSTEM. 


is  about  to  commence,  while  a  third  supply  is  caused  by  the 
induction  of  the  flame  or  by  the  draught ;  this  latter  supply 
comes  through  the  fire-bars,  and  in  special  cases  through  a 
hollow  furnace  front,  passing  between  the  inner  and  outer 
plate,  and  escaping  through  a  coned  opening  around  the  burner. 
No  change  in  the  arrangement  of  the  furnace  as  designed  for 
the  use  of  coal  is  necessary,  and  to  equip  the  furnace  for  burning 
liquid  fuel  it  is  only  necessary  to  cover  the  fire-bars  with  broken 
fire-bricks  to  a  depth  of  from  6  to  8  in.,  the  greater  depth 
being  towards  the  bridge.  The  burners  are  arranged  to  hinge 
on  the  air  and  oil  cocks  which  are  attached  to  the  boiler,  and 
if  it  is  necessary  to  examine  the  front  of  the  burners  they  can  be 
withdrawn  from  the  furnace,  the  act  of  withdrawing  shutting 
off  the  supply  of  air  and  oil,  and  thus  preventing  accident. 

Fig.  70  shows  the  steam  and  induced  air  burner.  The  oil  is 
pulverized  by  a  jet  of  steam.  Oil  enters  centrally  through 
the  branch  B,  and  has  a  whirling  motion  imparted  to  it  by  the 


THE  ATOMIZING  OF  LIQUID  FUEL 


255 


stem  of  the  oil  valve  G.  Steam  enters  around  the  hollow  cone 
H,  passing  through  slots  in  the  cylindrical  portion  where  this 
fits  into  the  hollow  of  the  air  cone,  the  whole  oil  supply  is  thus 
steam- jacketed.  The  air  cone  is  F,  and  this  is  also  fitted  with 
spiral  guides.  The  air  is  drawn  in  through  these  guides  by  the 
inductive  action  of  the  steam,  its  amount  can  be  adjusted  by 


N 


Fig.  70.     ATOMIZER.    KERMODE'S  STEAM  SYSTEM. 

opening  or  shutting  the  openings  D,  by  means  of  the  movable 
perforated  strap  E.  The  front  portion  F  is  arranged  to  screw 
in  or  out  as  a  whole,  being  turned  by  the  spider  M.  In  its 
motion  it  carries  with  it  the  air  cone  F,  and  thus  leaves  a  greater 
or  less  space  between  this  and  the  oil  cone  H,  for  the  escape 
of  steam.  The  range  of  adjustment  is  large,  and  the  same 
burner  may  be  used  for  different  powers  within  wide  limits. 


The  fydroleum 


Fig.  71.     ATOMIZER.     HYDROLETJM  SYSTEM. 

Fig.  71  shows  the  nozzle  of  the  Hydroleum  Company's  burner. 
Oil  is  centrally  regulated  by  a  needle,  and  issues  from  a  mouth- 
piece flared  out  externally  in  such  a  way  as  to  direct  the  atom- 
ized spray  slightly  outwards,  the  oil  being  in  the  middle.  The 
oil  mouthpiece  is  in  advance  of  the  steam,  and  an  inductive 
action  is  produced  which  draws  the  oil  forward  when  communi- 


256         LIQUID  FUEL  AND  ITS  APPARATUS 

cation  is  opened  with  the  reservoir.     The  Author  has  seen  this 
burner  acting  well  with  tar  as  fuel. 

External  hand  wheels  regulate  the  position  of  the  oil  and  air 
cones,  and  vary  the  amount  of  air  allowed  to  escape  round  the 

nozzle. 

An  elementary  form 
of  atomizer  consists 
simply  of  two  lengths 


of  gas  pipe,  one  in- 
Fig.  72.  side    the    other    for 

the   oil    and  steam. 

In  Fig.  72  this  is  shown  developed  somewhat,  the  steam  pipe 
being  swaged,  to  form  a  jet,  and  drilled  to  admit  the  oil. 
The  flame  of  this  burner  is  small,  and  produces  intense  local 
heat,  and  must  in  boiler  work  always  be  accompanied  by 
plenty  of  suitable  brickwork.  This  form  is  used  in  various 
forms  in  South  Russia. 

Of  self-atomizing  oil- jets  the  Korting  (Figs.  21  and  2 la)  has 


Fig.  73.     SWENSSON  ATOMIZER. 

been  considerably  employed  at  sea,  and  is  described  under  the 
head  of  the  Korting  System,  p.  153. 

Another  self -spraying  oil- jet  is  the  Swensson  (Fig.  73),  in 
which  the  oil  passes  through  a  fine  jet,  and  is  divided  into  spray 
by  striking  a  cutter  placed  a  little  in  front  of  the  orifice.  These 
self-sprayers  have  a  certain  advantage  of  simplicity.  No 


THE  ATOMIZING  OF  LIQUID  FUEL 


257 


bulky  air  pump  is  required,  to  compress  air,  for  atomizing  the 
oil.  There  is  no  waste  of  fresh  water  as  in  steam  atomizing. 
A  small  oil  pump  will  spray  all  the  oil  of  a  large  steamship,  as 
a  simple  calculation  will  show.  With  a  horse-power  of  5,000 
there  may  be  used  5,000  pounds  of  oil  per  hour,  or,  say,  10 
gallons  per  minute,  which  would  fill  a  three-inch  pipe  400 
inches  long.  Thus  a  three-inch  oil  pump  with  a  six-inch 
stroke,  if  run  at  sixty- 
seven  strokes  per 
minute,  or,  say,  thirty- 
four  revolutions,  would 
feed  oil  for  5,000  horse- 
power, and  two  or  three 
smaller  pumps  would  in 
practice  be  employed  in 
any  ship.  The  oil 
pumps  are  thus  very 
insignificant  in  size,  and 
this  fact  will  popularize 
the  self-spraying  ato- 
mizers if  they  prove 
satisfactory  under  ordi- 
nary conditions.  Of 
course,  the  oil  will  not 
spray  unless  heated 
sufficiently  to  be  limpid 
and  easily  flowing.  If 
too  viscous  it  will  spray 
in  strings,  and  not  burn 
as  thoroughly  as  it 
should. 


The  Symon-House 
Burner. 


This  is  one  of  the 
vaporizing  burners 
which  use  the  paraffin 
or  kerosine  grades  of  oil,  a  cellular  reservoir  above  the  flames 
serving  as  the  vaporizer  through  which  the  oil  travels  in  a  long 
circuitous  course,  passing  down  the  pipe  to  a  turned-up  jet 
below,  this  being  regulated  by  a  needle,  and  surrounded  by  a 
cone  which  conducts  air  to  the  flame.  Preliminary  heating 
by  a  lamp  of  petrol  or  alcohol  is  necessary.  This  burner  is 
used  for  small  launch  boilers,  and  is  shown  in  Fig.  74. 


SYMON-HOUSE  BUHNER  AND 
VAPORIZER. 


258 


LIQUID  FUEL  AND  ITS  APPARATUS 


It  is  claimed  that  in  small  work  atomizing  produces  too 
intense  a  heat,  and  that  vaporized  petroleum  is  better.  Steam 
can  be  raised  to  100  pounds  pressure  in  twelve  or  fifteen  min- 
utes, and  by  means  of  the  igniter  above  the  vaporizer  the  fire 
will  relight  after  several  minutes  if  put  out  by  a  sudden  jar  or  a 
gust  of  wind.  The  igniter  consists  of  a  hollow  disc  full  of 
broken  fire-brick. 

In  the  French  navy  the  Guyot  burner  has  been  much  used, 
This  is  shown  in  Fig.  75,  the  oil  entering  centrally  and  being 
impinged  upon  by  an  annular  jet  of  air  or  steam.  The  atomiz- 


Fig.  75.     GUYOT  ATOMIZER. 


ing  nozzle  should  not  project  as  in  Fig.  76,  but  should  be  kept 
short,  as  in  Fig.  77. 

The  Atomizing  Agent.  . 

Though  in  the  early  French  trials  of  1887  as  much  as  1-2 
pounds  of  steam  was  used  per  pound  of  oil,  the  quantity  was 
gradually  reduced  until,  in  1893,  less  than  half  a  pound  of 
steam  was  used  in  the  Godard  boiler,  says  M.  Bertin,  and  in 
1895  M.  Guyot  got  down  to  as  low  as  0-25,  results  which  also 
have  been  obtained  in  the  Italian  Navy.  Indeed,  on  a  Schichau 
torpedo  boat  as  low  as  0-102  is  claimed. 

Compressed  air,  said  M.  Bertin  some  years  ago,  has  some 
theoretical  advantages,  because  a  given  weight  of  steam  will 
compress  up  to  its  own  pressure  a  weight  of  air  superior  to 
itself,  and  the  pulverizing  effect  of  a  jet  depends  on  the  energy 


THE  ATOMIZING   OF  LIQUID  FUEL 


259 


of  the  jet  rather  than  upon  its  volume.     Probably  the  resis- 
tance of  the  machine  overbalances  any  theoretical  advantage, 
but  at  sea  the  loss  of  fresh  water,  where  a  steam  atomizer  is 
employed,    must   amount 
to    about    5  per   cent,  of 
the  total  steam  generated. 
M.  Bertin,  however,  said 
that  a  good  air  compressor 
will  not  use  half  the  steam 
necessary   where    this    is 
used  direct.     When  start- 


Fig.  76. 


NOZZLE  OF  GUYOT  ATOMIZER. 
INCORRECT  FORM. 


ing  from  the  cold  boiler, 
the  compressed  air  may 
be  raised  by  a  small 
compressor  driven  from  a  storage  battery,  by  a  small  petro- 
leum engine,  or  by  hand.  Steam  atomizing  is  open  to  the 
objection  that  should  priming  occur  the  fires  may  be  ex- 
tinguished, and  where  the  steam  comes  over  wet,  from  a 
priming  boiler,  it  is  quite  common  for  burners  to  be  ex- 
tinguished, and  the  red-hot  brickwork  fails  t j  ignite  the  oil, 
and  it  is  necessary  to  do  this  by  means  of  a  flaming  torch. 
Steam  should  therefore  be  superheated,  both  to  render  it  dry 
and  to  improve  its  general  action. 

M.  d'Allest  found  in  VAude  that  atomizing  by  steam  used 
up  15  per  cent,  of  the  total  steam  produced.  A  little  later, 
at  Cherbourg,  the  Torpedo-boat  22  used  as  little  as  1-2  k., 
and  the  Buffle  only  0-75  k.,  per  kilo,  of  oil  pulverized,  until 

finally  the  results  as 
detailed  above  were 
secured,  though  actual 
facts  are  not  easy  to 
obtain,  and  tests  require 
to  be  undertaken  with 
a  special  boiler  to  supply 
atomizing  steam.  Re- 
sults of  0-5  and  0-7  are 
frequently  obtained,  and 
have  gone  below  0-3. 
Such  a  figure  as  this  is 
to  be  considered  very  good  indeed.  To  save  fresh  water  at  sea 
is  so  much  to  be  desired  that  could  compressed  air  be  substi- 
tuted for  steam  it  should  be.  M.  Bertin,  formerly  favourable 
to  air  as  more  economical,  saw  reasons  to  change  his  views. 
Air  was  necessary  at  much  higher  pressure  than  that  required 
for  forced  draught.  It  is  affirmed  that  1-4  k.  of  steam  at  6  k. 


Fig.  77. 


NOZZLE  OF  GUYOT  ATOMIZER. 
CORRECT  FORM. 


260          LIQUID  FUEL  AND  ITS  APPARATUS 

pressure  must  be  expended  to  compress  1  kilo,  of  air  to  1*5  k., 
and  more  air  must  be  expended  to  pulverize  each  unit  of  oil 
as  compared  with  steam.  Thus  Torpedo-boat  60  at  Cherbourg 
expended  0-6  k.  to  0-8  k.  of  air  in  place  of  04  k.  of  steam. 

During  a  test  at  Indret  not  less  than  0-5  k.  of  air  was 
expended.  In  brief,  with  ordinary  apparatus  to  obtain  2  k.  of 
air,  which  is  needed  to  do  the  work  of  1  k.  of  steam  used  direct, 
one  must  use  3  k.  of  steam  in  the  compression  engine. 

The  difficulty  is  that  compression  is  slow  in  an  ordinary 


Fig.  78.     BOILER  or  FRENCH  TORPEDO-BOAT  No.  22. 


machine,  and  steam  cannot  be  used  economically,  for  the  air 
attains  its  highest  pressure  when  the  steam  is  ready  to  exhaust, 
and  a  heavy  flywheel  is  necessary  to  help  the  expanded  steam. 
M.  Bertin  is  further  impressed  with  the  physical  and  chemical 
advantages  of  steam,  which,  he  affirms,  secures  the  Ragosine 
effect  as  utilized  in  the  distillation  of  petroleum  without  crack- 
ing, owing  to  a  certain  solvent  action  of  steam  on  petroleum, 
as  yet  little  understood. 

The  particular  form  of  the  Guyot  atomizer  (Fig.  75)  is  that 
of  Torpedo  boat  No.  22,  the  furnace  of  which  is  shown  in  Fig. 
78,  the  boiler  being  of  return  tube  type.  M.  Bertin  finds 


THE  ATOMIZING  OF  LIQUID  FUEL 


261 


from  French  experience  that  though  regulation  of  an  oil 
atomizer  is  most  delicately  effected  by  means  of  the  central 
needle  of  the  feed  water  injector,  yet  a  valve  is  a  less  delicate 
detail,  and  many  atomizers  have  no  central  moving  cone, 
but  are  regulated  solely  by  valves. 

It  is  necessary  when  atomizing  that  the  steam  should  flow 
at  a  certain  speed.  If  too  rapid,  the  flame  is  extinguished  ; 
if  too  slow,  there  is  incomplete  pulverization,  and  the  oil  escapes 
in  drops  too  large  to  burn  well. 

Hence  the  steam  orifice  must  be  regulated  to  suit  the  boiler 
pressure.  ^ 

The  opening  for  oil  should  not  be 
less  than  1  mm.  =  2V  inch.  If  too 
large  the  oil  flows  in  too  great  a 
quantity.  It  is  essential  that  steam 
or  air  and  oil  shall  be  capable  of 
regulation  when  at  work,  and  that 
the  interior  of  the  atomizer  should 
be  readily  removed  while  at  work, 
so  that  the  orifices  can  be  cleared 
quickly  and  the  whole  replaced  im- 
mediately. 

After  numerous  experiments  with 
atomizers  producing  both  thin  flat 
jets,  and  thin  annular  or  cylindrical 
jets,  M.  d'Allest  devised  the  atomizer 
of  Fig.  79,  for  which  are  claimed  the 
best  results  in  regularity  of  effect 
and  steady  working.  It  is  very  Fig  79  D>ALLEST  ATOMIZER. 
simple  in  form,  and  can  be  rapidly 

dismounted  for  cleaning.  It  consists  of  an  outer  case  con- 
taining an  inner  cone  and  spindle  ;  a  steam  inlet  at  the 
side  N  admits  steam  to  the  casing.  The  whole  is  attached 
to  a  conical  mouthpiece.  Steam  is  regulated  by  a  valve, 
and  escapes  round  the  two  cones,  while  oil  comes  round  the 
central  spindle. 

Air  is  induced  through  the  surrounding  opening  E. 

The  cone  can  be  screwed  upon  the  nose  of  the  case  for  par- 
tial adjustment  of  the  steam,  which  is  further  regulated  by  a 
valve  in  the  steam  pipe.  M.  d'Allest  places  these  vaporizers, 
if  necessary,  in  couples  in  one  furnace,  connecting  them  to  the 
same  oil  pipe  to  the  number  of  three,  or  even  four. 

Each  burner  will  dispose  of  from  10  to  80  kilos.  =  22  to  176 
pounds  of  oil  per  hour.  Two  burners,  using  each  80  kilos,  of 
oil,  will  evaporate  13  kilos,  of  water  per  kilo,  of  oil,  or  say  2,080 


262         LIQUID  FUEL  AND  ITS  APPARATUS 

litres  per  hour  =  4,576  gallons.  Allowing  30  litres  per  square 
metre  of  heating  surface  ;  about  6  pounds  per  square  foot ; 
these  two  burners  should  serve  a  boiler  of  70  square  metres  of 

heating     surface    or    753 
square  feet. 

In  a  torpedo  boat,  how- 
ever, the  desired  evapor- 
ation exceeds  this  amount 
per  square  metre.  With 
this  in  view,  M.  d'Allest 
has  designed  a  double 
atomizer,  in  which  oil  is 
admitted  round  the  cen- 
tral tube  in  an  annular 
jet.  Steam  comes  out- 
side this,  and  hot  air  is 
induced  round  the  whole, 
the  heating  being  effected 
by  a  tube  in  the  chimney. 
This  apparatus  (Fig.  80) 
will  burn  as  much  as  400 
kilos.  =880  pounds  of  oil 
per  hour  without  a  trace 
of  smoke. 


She  am 
Fig.  80.     D'ALLEST  DOUBLE  ATOMIZER. 


It  was  tried  in  VAude,  one  of  the  ships  of  the  Compagnie 
Frassinet.  A  weight  of  120  kilos,  of  oil  per  hour  =  264 
pounds,  produced  170  horse-power,  the  evaporation  being  14-1 
units  of  water  per  unit  of  oil,  but  the  French  Navy  considered 
12  units  as  the  maximum  that  should  be  calculated  upon. 


FvardofsJci  System. 

This  system  applied  to  locomotives  consists  in  the  placing  of 
an  atomizer  in  each  wall  of  the  furnace  two  and  two  exactly 
opposite,  the  jets  meeting  centrally  and  promoting  mixture. 
The  grate  is  covered  with  fire-bricks,  between  which  air  enters. 

Though  a  special  pulverizer  was  used,  it  would  appear  that 
any  atomizer  could  be  arranged  on  this  system. 

The  Brandt  burner  consisted  of  a  circular  box,  with  a  tapered 
slot  all  round  it  nearly  closed  by  the  edge  of  a  disc.  Steam 
escaped  under  the  disc  and  oil  above  it.  The  burner  was  set 
in  the  middle  of  the  fire-box  and  gave  a  large  hollow  flame,  but 
it  had  the  disadvantage  of  being  inaccessible  when  at  work, 
and  the  flame  was  easily  extinguished,  as  by  the  slipping  of  the 


THE  ATOMIZING  OF  LIQUID  FUEL  263 

wheels  of  a  locomotive,  the  sudden  pull  of   the   blast  extin- 
guishing the  flame  and  chilling  the  box. 

The  Soliani  burner  (Fig.  81)  is  of  simple  form,  resembling  the 
scent  spray. 

There   are  numerous   other  forms,   some   complex,   others 
crude,  but  to  enumerate  all  would  occupy  great  space,  and 
serve  no  good  purpose.      Those  illustrated 
will  show  the  general  trend  of  practice  and 
what  has  been  done,  the  chief  point  being 
apparently  that  the  annular  form  of  jet 
is  preferable  and  conduces   to  best  mix- 
tures. 

The    difficulty    with     burners     which 
vaporize  has  been  the  deposit  of  carbon. 
This  will  occur  even  with  kerosene,  the        Fig  gl     gOLIANI 
carbon   being   a  pulverulent  coke.     The  BURNER. 

difficulty  was  got  over  by  M.  Serpollet  by 
means  of  easily  replaced  burners.  Heavy  oils  can  then  be 
burned.  Too  high  a  heat  seems  to  be  the  cause  of  carbon 
deposit,  the  oil  being  "  cracked  "  exactly  as  in  a  highly  heated 
still.  At  present  not  much  is  being  done  by  vaporizers,  at 
least  for  large  powers,  the  atomizer  becoming  more  general. 

On  the  question  of  pre-heating,  the  French  Naval  tests  are  in 
accord  with  others  as  to  the  advantage  of  this. 

Long  recognized  as  an  advantage  to  heat  to  80°C.  =  176°F., 
it  is  to-day  established  that  Mazout  may  well  be  heated  to  132° 
C.  =269-6°F. 

At  this  temperature  the  fuel  gives  off  a  certain  amount  of 
vapour,  which  raises  the  pressure  in  the  burner,  helps  the 
velocity  of  the  jet,  and  ignites  promptly  at  the  nozzle,  and 
assists  the  combustion  of  the  whole.  Heating  the  oil  raises 
the  efficiency  of  the  combustion,  cuts  short  the  flame,  and 
increases  the  effect  of  the  heating  surface. 

It  is  not  desirable  to  generate  too  much  vapour  at  the  orifice 
of  the  atomizers,  or  no  air  can  gain  access  to  the  jet,  and  com- 
bustion cannot  occur.  Air  admixture  is,  of  course,  necessary, 
and  when  atomizing  is  done  with  compressed  air  this  is  a  mere 
fraction  of  the  total  air  required.  The  air  itself  is  best  heated, 
especially  if  this  can  be  done  by  recuperation  of  otherwise 
wasted  heat. 

The  object  of  an  atomizer  is  to  fill  the  furnace  with  flame,  and 
the  furnace  must  avoid  contact  with  the  flame  pending  complete 
combustion.  The  accomplishment  of  these  various  ends  has 
brought  about  the  many  forms  of  atomizers  already  described. 
All  of  them  bear  a  strong  family  resemblance.  In  Russia 


264         LIQUID  FUEL  AND  ITS  APPARATUS 

there  appears  a  tendency  to  employ  flat  jets.  Hence  also  the 
various  forms  of  furnace  with  their  refractory  linings  of  fire- 
brick, as  in  Fig.  82  annexed,  which  represents  a  boiler  made  at 
Cherbourg  in  1893,  and  bears  a  general  resemblance  to  the 
much  older  forms  devised  by  Urquhart.  In  this  boiler  the 
atomizers  are  placed  as  shown  in  the  side  walls  of  the  furnace. 

Railway  practice  in  America  tends  to  the  use  of  flat  jets. 
On  the  Southern  Pacific  Railway  a  simple  atomizer,  which 
allows  the  oil  to  fall  from  an  orifice  over  the  front  of  a  flat 
steam  jet,  has  this  jet  3  J  inches  wide.  The  petroleum  escapes 
at  an  orifice  half  an  inch  high  and  of  the  length  of  three  inches, 
the  steam  opening  being  about  0-8  mm.  high,  or  -3V  inch.  The 


Fig.  82.     LOCOMOTIVE  TYPE  BOILER  TESTED  AT  CHERBOURG  WITH  LIQUID 

FUEL. 


width  of  the  jet  of  steam  is  3  J  inches,  extending  J  inch  at  each 
end  below  the  flow  of  oil,  so  that  no  oil  escapes  unatomized. 
Flat  pulverizers  are  stated  by  M.  Bertin  to  be  suitable  for 
boilers  of  the  Belleville  or  Niclausse  type,  in  which  the  flames 
rise  directly  from  the  grate  to  the  water- tubes.  The  broad 
flat  flame  probably  burns  over  a  wide  area,  and  does  not  enter 
between  the  pipes  so  rapidly  as  if  it  were  a  less  wide  spreading 
jet. 

Should  a  pulverized  jet  encounter  a  cold  boiler  plate  at  a 
temperature  of  400°  to  500°C.  —  752°  to  932°F.,  the  oil  will 
condense  on  the  plate  and  not  again  ignite. 

In  the  boiler  of  Torpedo-boat  No.  22  (Fig.  78)  the  furnace  is 
fitted  with  an  air  advance  chamber  in  which  oil  is  atomized 
and  meets  air  streams  admitted  radially.  The  furnace  is 


THE  ATOMIZING  OF  LIQUID  FUEL  265 

brick-lined,  with  a  low  striking  bridge.  In  this  boiler  11*6 
kilo,  and  10 -8  kilo,  of  water  have  been  evaporated  per  kilo, 
of  oil  with  a  draught  of  20  to  30  mm.  (1  inch  mean)  of 
water.  At  heavier  draughts  of  95  to  1 10  mm.  water  gauge 
(or  a  mean  of  four  inches),  only  9- 45  k.  and  8-5  k.  were 
evaporated.  A  similar  boiler,  with  the  air  arriving  parallel 
with  the  jet,  however,  evaporated  13-25  k.  of  water,  which 
shows  the  difference  due  to  arrangements. 

It  may  be  stated  finally,  that,  of  all  atomizers,  the  more 
successful  are  those  which  atomize  the  oil  right  at  the  nozzle 
or  point  of  exit.  This  class  appears  least  liable  to  choke  with 
dirt  or  to  permit  of  the  oil  becoming  carbonized  within  the 
body  of  the  atomizer. 

Where  atomizers  are  applied  through  the  furnace  door  they 
are  arranged  to  swing  back  upon  a  trunnion  hinge  so  designed 
as  to  shut  off  the  fuel  supply  when  the  atomizer  is  swung  back. 

The  body  part  on  which  the  atomizer  branches  are  connected 
swivels  in  the  two  end  pieces  through  packed  glands  and  these 
end  pieces  receive  the  oil  and  steam  or  air  pipes  which  supply 
the  fuel  and  atomizing  agent. 

The  tendency  at  the  present  time  seems  to  be  somewhat  in 
the  direction  of  doing  without  both  air  and  steam  as  atomizing 
agents  and  relying  entirely  on  the  pumped  pressure  of  well 
sieved  and  heated  oil  to  effect  the  necessary  atomization. 

Mixed  systems  must  long  continue  to  be  employed,  burning 
solid  and  liquid  fuel  in  the  same  furnace. 

Twenty  years  ago  the  calorific  value  of  the  world's  oil  pro- 
duction was  but  one-twentieth  of  the  heat  value  of  coal. 
To-day  (1921)  the  ratio  has  risen  to  one-tenth,  but  it  is  still 
a  far  cry  to  the  day  when  coal  will  be  passed  in  the  race,  if 
indeed  such  a  day  can  ever  arrive. 

The  majority  of  fuel-burning  plants  must  still  be  either  of 
sclid  fuel  or  of  mixed  type,  and  the  greater  the  number  of 
all- liquid  plants  which  come  into  use  the  less  oil  will  there  be 
for  other  consumers. 

The  Gregory  Burner. 

This  burner  (Fig.  82a)  consists  of  a  central  oil  passage 
placed  within  a  steam  cone,  the  oil  being  regulated  by  a  central 
needle  or  spindle  valve  with  hand  wheel  as  shown,  and  the 
steam  by  the  usual  supply  valve.  Air  mixed  with  highly 
heated  furnace  gas  is  drawn  by  the  inductive  action  of  the 
steam  into  a  chamber  surrounding  the  atomizing  nozzle,  and 
serves  to  gasify  the  already  heated  oil  and  greatly  to  aid  and 
render  perfect  its  combustion. 


265A  LIQUID  FUEL  AND  ITS  APPARATUS 

Suitable  clearing  plugs  are  provided.  By  this  burner  it 
has  been  found  possible  to  burn  any  inferior  solid  fuels  by  the 
use  of  small  quantities  of  oil  without  smoke,  and  otherwise 
impracticable  fuels  may  be  employed  with  very  considerable 
resulting  economy. 

The  heated  gases,  drawn  from  the  furnace,  thoroughly  dry 
and  superheat  the  steam,  the  temperature  of  the  mixed  vapours 
being  moderated  by  admission  of  cold  air  by  the  inlet  indi- 
cated in  the  figure. 

The  burner  shown  is  of  locomotive  type,  but  the  system  is 
equally  applicable  to  stationary  boilers  and  may  also  be  em- 
ployed in  furnaces  with  oil  fuel  alone. 

One  of  its  great  advantages  is  the  manner  in  which  inferior 
fuels  may  be  enabled,  by  the  use  of  a  small  quantity  of  oil, 
to  improve  their  combustion  by  the  increment  of  furnace 
temperature  that  may  be  brought  about  by  the  oil.  This 
is  a  valuable  feature  in  view  of  the  great  amount  of  inferior 
coal  now  to  be  found  on  the  market.  This  was  recognized  by 
M.  Bertin  of  the  French  Navy  many  years  ago,  but  the  Gregory 
burner  enables  such  necessary  temperatures  to  be  more  readily 
attained. 

Great  stress  is  laid  on  the  gasification  of  the  oil  by  the  hot 
gas.  Assuming  1  pound  of  gas  drawn  in  at  2000  °F.  from  the 
furnace  and  a  specific  heat  of  0-25  ;  which  according  to  Ber- 
thelot's  researches  should  be  much  under  the  truth  for  high- 
temperature  gas  ;  there  will  be  500  B.Th.U.  added  to  the  oil. 

One  pound  of  oil  has  a  latent  heat  of  vaporization  probably 
not  over  half  that  of  w^ater,  so  that  1  pound  of  hot  gas  should 
fully  vaporize  1  pound  of  oil,  and  such  hot  gas  would  only  be 
a  small  fraction  of  the  weight  of  the  air  necessary  for  com- 
bustion. 

The  claims  for  this  burner's  good  performance  thus  appear 
to  have  a  properly  sound  thermal  basis.  Probably  some  of 
the  good  performance  may  be  the  result  of  the  gasification 
of  the  hot  oil  in  an  atmosphere  giving  little  or  no  support  to 
combustion,  so  that  the  hydrogen  is  not  abstracted  too  soon, 
leaving  the  nascent  carbon  to  assume  the  difficult  state  of  a 
gas  carbon  similar  to  the  well-known  retort  carbon  of  the 
gasworks. 


26  5B 


CHAPTER    XIX 

METALLURGY.      THE   HOVELER  PROCESS 

IT  is  outside  the  intended  scope  of  this  book  to  deal  very 
seriously  with  the  metallurgical  applications  of  liquid 
fuel.  The  author  dealt  with  this  at  some  length  in  Liquid 
Fuel  and  Its  Combustion. 

Since  that  book  was  written  there  has  been  perhaps  fully 
as  much  progress  in  the  metallurgical  application  as  in  power 
application. 

If  in  a  furnace,  ore  or  metal  is  acted  upon  too  close  to  the 
point  of  initial  combustion  of  the  oil  the  flame  will  be  power- 
fully oxydizing  and  therefore  inoperative  for  reducing  work. 
As  shown  in  the  above  book,  the  oil  must  be  burned  in  a  separate 
chamber,  in  advance  of  the  working  furnace. 

This  is  accomplished  in  the  "  Hoveler  "  system  by  placing 
the  oil  atomizer,  actuated  by  compressed  air  at  15  pounds 
pressure,  behind  a  small  conical  retort  lined  with  refractory 
material.  Ignition  occurs  as  the  atomized  jet  enters  this  cone, 
the  flame  tapering  outwards  within  the  cone  and  coming  out 
by  a  circular  orifice.  This  apparatus  can  be  carried  about  on  a 
wheeled  standard  or  slung  in  a  chain  and  placed  outside  any 
furnace  it  is  desired  to  heat.  The  cylindrical  bar  of  flame  passes 
through  an  opening  of  its  own  diameter — a  few  inches — and 
will  maintain  the  interior  of  a  large  rotary  furnace,  or  of  an  air 
furnace  at  a  high  temperature.  By  suitable  regulation  the 
effect  obtained  can  be  oxydizing  or  reducing  according  to  the 
amount  of  air  admitted.  By  this  system  very  high  efficiency 
of  the  fuel  is  obtained,  but  as  in  all  metallurgical  processes 
which  involves  high  temperature  work  the  effluent  gases  must 
inevitably  carry  away  heat  proportionate  to  the  temperature. 

The  atomizer  of  the  Hoveler  system  (Fig.  65)  receives  the  oil 
via  a  in  a  central  tube  h,  in  which  is  a  needle  stem  /  that  con- 
verts the  orifice  into  an  annulus  c.  Compressed  air  comes  via 
b  outside  the  conical  end  of  this  oil  tube  by  the  tube  g  and  the 
atomized  jet  is  discharged  into  a  cone  i,  through  which  atmo- 
spheric air  is  induced  to  flow  via  d.  The  treble  mixture  issues 


METALLURGY:  THE   HOVELER  PROCESS     267 

by  a  parallel  opening  d  projecting  through  a  larger  opening  e, 
which  can  be  made  to  supply  a  further  amount  of  compressed 
air  if  needed  via  c. 

For  a  reducing  flame  the  compressed  air  is  supplied  at  only 
10  pounds  pressure,  and  in  reducing  ores  or  oxides  small  coal 
may  be  mixed  with  the  stuff  to  be  reduced,  its  duty  being  to 
supply  carbon  the  more  energetically  to  absorb  the  oxygen 
of  the  heated  material.  The  use  of  liquid  fuel  in  metallurgical 
work  possesses  all  the  advantages  of  convenience,  cleanliness, 
control  and  time  saving  which  appertains  to  its  use  in  steam 
raising,  and  in  metallurgy  there  is  also  a  marked  economy 
in  the  percentage  of  reduction  and  improved  product.  Though 
much  dearer  per  ton  than  coal,  liquid  fuel  gains  very  consider- 


Fig.  65.     HOVELER  ATOMIZER. 

ably  by  reason  ot  the  amount  of  it  that  is  not  used,  for,  where  a 
heat  must  be  maintained  to  the  last  the  coal  fire  is  left  large 
and  active,  but  the  oil  flame  is  shut  off  at  once.  Oil  gains  by 
reason  of  superior  efficiency  in  the  application  of  the  heat  pro- 
duced. 

The  Aerated  Fuel  Process. 

This  process  of  the  Gilbert  and  Barker  Co.  of  New  York 
is  simply  a  system  of  atomizing  by  compressed  air,  and  is  used 
in  all  manner  of  industrial  arts,  the  flame  being  used  direct 
in  metal  work,  glass  making,  japanning,  etc.  The  apparatus 
includes  an  air  compressor,  oil  pump  and  receiver,  storage 
tank  and  the  burners  and  necessary  pipes. 

Compression  is  to  15  pounds  per  square  inch,  a  pressure 
below  which  it  is  stated  that  the  fuel  is  not  perfectly  atomized. 


268          LIQUID  FUEL  AND  ITS  APPARATUS 

The  oil  pump  is  itself  worked  by  the  air,  and  serves  to  keep 
a  full  receiver  of  about  30  gallons  capacity  (25  imperial  gallons). 
The  receiver  also  contains  compressed  air  which  forces 
the  oil  to  the  burner  (Fig.  67),  where  it  meets  the  air 
coming  direct  from  the  compressor.  Valves  regulate  the 
proportions  and  the  air  pressure  preserves  even  working  con- 
ditions, whether  two  or  twenty  burners  are  at  work.  It  is 
claimed  that  the  combustion  is  really  gaseous,  clean  and  smoke- 
less. The  main  supply  is  a  buried  tank  outside  the  building 
and  away  from  the  burners.  The  oil  pump  is  automatically 
regulated  by  a  float,  and  all  apparatus  is  below  the  burners, 
so  that  no  gravity  flow  can  take  place.  The  use  of  gravity  is 
held  by  some  to  be  bad  practice,  and  this  view  will  bear  argu- 
ment in  its  favour.  Low  pressure  air  is  condemned  as  leading 
to  imperfect  atomization  and  large  globules  which  burn 
imperfectly  and  deposit  carbon  and  injure  the  fire-brick. 
From  60  to  120  gallons  of  oil  are  claimed  to  do  the  work  of  a 
ton  of  coal. 

The  process  is  held  to  be  much  superior  to  any  steam  atomiz- 
ing process  for  metallurgical  work. 

Low  pressure  air  which  throws  oil  upon  the  fire-brick  uncon- 
sumed,  causes  these  to  shell  off  and  break,  and  smoke  is  made 
also  while  carbon  is  deposited  in  the  furnace. 

Applied  to  metallurgy,  to  forge  furnaces,  crucible  heating, 
and  other  industrial  work  outside  steam  raising,  the  advantages 
of  oil  fuel  are  not  merely  absence  of  dirt  and  dust,  but  there  is 
no  loss  of  time  through  men  waiting  for  fires  to  burn  up.  There 
are  no  times  of  good  or  of  bad  fires,  no  uneven  heat,  but  a  full 
flowing  flame  is  maintained  with  an  even  continuous  degree  of 
heat.  Then  the  economy  of  oil  is  largely  secured  by  increased 
production  and  better  work.  Oil  has  the  advantage  over  gas 
fuel  also,  which,  though  equally  good  in  the  furnace,  cannot  be 
produced  without  labour  and  dust  and  at  a  considerable 
outlay  in  plant  and  apparatus. 

The  calorific  capacity  of  various  gases  is  as  per  following 
table — 

Heat  Units  per 
thousand  cubic  feet. 

Natural  gas 1,000,000 

Air  gas  (gas  machine)  20-candle  power  .  .  815,500 
Public  illuminating  gas,  average  ....  650,000 
Water  gas  (from  bituminous  coal)  .  .  .  377,000 
Water  and  producer  gas  (mixed)  ....  175,000 

Producer  gas 150,000 

Blast  furnace  gas 100,000 

Since  a  gallon  of  fuel  oil  (7  pounds)  contains  151,000  heat 


METALLURGY:  THE  HOVELER   PROCESS      269 

units,  the  following  comparisons  may  be  made.  At  three  cents 
a  gallon  (about  l-8d.  per  English  gallon),  the  equivalent  heat 
units  in  oil  would  be  equal  to — 

Dollars  per 
thousand  cubic  feet. 

Natural  gas at  -1987 

Air  gas  20-candle  power ,     -1620 


Public  illuminating  gas,  average  . 
Water  gas  (from  bituminous  coal) 
Water  and  producer  gas  (mixed)  . 

Producer  gas 

Blast  furnace  gas 


•1291 
•0749 
•0347 
•0298 
•0200 


At  four  cents  a  gallon  (about  2-4cZ.  per  English  gallon)  the 
equivalent  heat  units  in  oil  would  equal — 


Dollars  per 
thousand  cubic  feet. 


Natural  gas     .  at  -2649 

Air  gas,  20-candle  power ,     '2160 

•1722 
•0998 
•0463 
•0397 
•0265 


Public  illuminating  gas,  average  . 
Water  gas  (from  bituminous  coal) 
Water  and  producer  gas  (mixed)  . 

Producer  gas 

Blast  furnace  gas 


so  that  when  oil  will  pay  to  use  it  may  be  installed  at  one-tenth 
the  cost  of  a  gas  plant  and  worked  for  a  fraction  of  the  cost  in 
upkeep  and  wages. 

The  Springfield  System  uses  air  as  low  as  18  or  24  ounces 
pressure  ;  oil  comes  forward  at  forty  pounds  pressure.  This 
apparently  contradicts  the  statements  above,  that  low  pressure 
air  is  not  satisfactory.  Possibly  an  explanation  is  to  be  found 
in  the  oil  pressure  which,  as  in  the  Korting  system,  should 
itself  do  much  towards  atomizing  the  oil.  Clearly  the  oil 
must  possess  energy  of  itself  or  borrowed  from  compressed  air 
or  steam. 


Colloidal  Fuel  (1921). 

During  the  past  few  years  the  colloidal  state  has  been 
attracting  considerable  attention,  especially  in  the  direction 
of  medicine. 

The  term  colloidal  properly  applied  appears  to  pertain  to 
a  condition  or  atomic  state  assumed  by  substances  under 
certain  conditions,  such  for  example  as  the  milky  condition 


269A          LIQUID  FUEL  AND  ITS  APPARATUS 

of  calcium  carbonate  when  thrown  out  of  solution  in  water 
when  the  excess  molecule  of  C02  is  removed  by  caustic 
lime. 

So-called  colloidal  fuel  is  that  modern  form  produced  when 
finely  divided  carbonaceous  matter  is  mixed  with  liquid 
hydrocarbons  so  as  to  produce  by  practically  a  colloidal  mix- 
ture or  one  which  will  not  separate  out  into  a  liquid  and  a 
solid  deposit.  The  continuity  of  the  suspension  appears  to 
be  secured  by  the  use  of  certain  added  products  known  as 
"  fixateurs." 

Such  a  colloidal  fuel  may  be  used  in  an  appropriate  burner 
and  sprayed  exactly  as  fuel  oil. 

It  has  been  found  practicable  with  suitable  forms  of  soft 
coals  to  add  as  much  as  1-2  pounds  of  coal  to  1-25  pounds  of 
oil,  while  at  the  same  time  the  bulk  is  but  little  increased. 
In  the  ordinary  way  a  gallon  of  oil  weighing  9J  pounds  per 
gallon  can  be  loaded  up  with  coal  until  it  weighs  12  pounds 
per  gallon.  Obviously  the  storage  capacity  of  a  given  bunker 
space  is  very  much  increased,  for  example — 


B.Th.U.         B.Th.U. 

9-6  Ib.  of  oil at  17,500  =  166,250 

2-6  Ib.  of  coal  .      .  ,  11,000  =     27-500 


Total  in  same  volume  =  193,750 

or,  say,  17  per  cent,  additional  calorific  capacity  per  unit  of 
bunker  space. 

With  special  coal  and  the  ratio  12-12-5  as  above  named 
the  results  are  as  follows  : — 

B.Th.U.          B.Th.U. 

1-25  Ib.  of  oil at  17,500  =  21,875 

1-2  Ib.  of  coal „  10,000  =  12,000 

33,875 

or  equivalent  to  an  increased  unit  calorific  carrying  power  of 
bunkers  of  33J  per  cent.  Thus  much  longer  voyages  can  be 
made  without  rebunkering. 

The  subject  is  too  novel  for  further  reference,  but  if  present 
indications  hold  good  in  respect  of  permanency  of  condition, 
the  subject  of  colloidal  fuel  must  inevitably  come  into  very 
prominent  view.  Much  is  being  done  by  Mr.  Lewis,  of  the 


METALLURGY:  THE   HOVELER  PROCESS     269B 

Fuels  Laboratory,  Dacre  Street,  Westminster,  to  whom  I  am 
indebted  for  the  foregoing  figures,  in  respect  of  the  chemical, 
physical  and  mechanical  examination  of  coals  generally,  and 
many  curious  and  valuable  facts  are  coming  to  light. 


CHAPTER    XX 

THE   OIL   ENGINE 

OIL  or  liquid  fuel  engines  may  be  divided  into  five  classes  : 
— (a)  Those  which  use  the  lightest  distillates  of  petro- 
leum. They  are  known  as  petrol  engines  and  they  are  strictly 
only  a  form  of  gas  engine,  for  the  liquid  they  use  is  only  admit- 
ted to  a  vessel  through  which  the  engine  draws  its  air  supply. 
The  air  is  thus  carburetted  or  petrolized,  no  liquid  molecules 
remaining,  and  ignition  is  electrical.  It  is  not  intended  to  treat 
further  of  this  class. 

(b)  The  paraffine  engine  which  employs  the  commoner  grades 
of  lamp  oil. 

(c)  Crude  or  heavy  oil  engines  which  are  fed   with   heavy 
oils. 

(d)  The  Diesel  engine,  in  which  the  fuel  is  sprayed  into  pure 
air  so  highly  compressed  as  to  be  at  a  red  heat. 

(e)  The   Griffin   engine,  which  rejects   incombustible  bases 
such  as  asphaltum. 

A  brief  description  of  the  latter  four  types  will  be  sufficient 
to  show  the  application  of  liquid  fuel  to  internal  combustion 
engines. 

Class  &.  The  Hornsby  engine  (Fig.  83)  may  be  taken  to  illus- 
trate this  class.  On  the  back  cover  of  the  cylinder  is  fixed  a 
bottle  neck  vaporizer,  V,  which  is  first  heated  by  a  lamp  and  is 
afterwards  kept  hot  by  the  explosions  within  it  when  the  engine 
has  been  set  to  work. 

The  back  of  the  cylinder  beyond  the  piston  stroke  forms, 
with  the  vaporizer,  the  compression  space.  Air  drawn  into  the 
cylinder  on  the  outstroke  of  the  piston  is  compressed  into  the 
vaporizer,  into  which  oil  is  forced  as  spray  by  a  small  pump 
at  the  moment  of  highest  compression.  The  oil  is  vaporized 
by  the  heat  of  the  air,  and  the  mixture  ignites  and  expands 
into  the  cylinder  through  the  bottle  neck.  The  oil  pump  works 
always  at  full  capacity,  but  a  by-pass  allows  part  of  it  to 
escape  back  to  the  tank.  This  by-pass  is  controlled  by  the 
governor.  About  0-55  pint  of  oil  (of  -825  sp.  gr.)  per  B.H.P. 

27Q 


THE   OIL  ENGINE  271 

hour  is  consumed.     The  engine  will  use  oil  of  0-79  to  0-88  sp. 
gr.,  and  even  heavier  or  crude  oil  may  be  used. 

An  engine  of  over  100  B.H.P.  was  run  continuously  night 
and  day  for  500  hours  =21  days.  At  the  end  of  the  time 
there  was  practically  no  deposit  in  the  vaporizer  and  the  engine 
would  have  run  a  much  longer  period  without  loss  of  power. 
The  oil  used  was  the  thickest  Texas  liquid  fuel,  and  at  the  end 
of  the  run  the  engine  was  working  as  well  as  at  the  beginning. 
The  particulars  of  the  run  are  as  below  :— 

T?af^r>TT-p  /  no  B.H.P.  for  refined  oil. 

1 100  B.H.P.  for  residual  oil. 

Total  number  of  hours  running 502 £ 

Fuel  used     .      .      .      Texas,  costing  3d.  per  gallon  in  tank  wagons. 

Specific  gravity -933 

Flash  point  (open  test) 240°  F. 

Total  amount  of  fuel  used    ....        15  tons  5  cwt.  1  qr.  17  Ib. 

Amount  used  per  hour 68*07 

Average  brake  horse -power 100*8 

Amount  of  fuel  used  per  B.H.P.  hour  ....      -578  pints. 

Cost  of  fuel  per  B.H.P.  hour  -21675d. 

Or  for  100  B.H.P. Is.  9£d.  per  hour. 

Or  4-6  B.H.P.  for Id.  per  hour. 

The  method  of  injection  at  the  time  of  ignition  probably 
ensures  as  full  a  combustion  of  all  the  oil  as  is  practicable,  none 
depositing  before  it  has  had  a  chance  to  burn.  This  helps  to 
prevent  distillation  to  destruction  or  "  cracking  "  which  hap- 
pens when  oil  is  too  highly  heated.  The  lighter  parts  are  driven 
off  as  vapour  and  heavy  residuals  are  left  and  may  accumulate 
in  the  vaporizers  as  solid  carbon. 

This  need  not  occur  with  paraffine,  which  should  never  be 
made  so  hot  that  it  will  not  condense  into  the  same  liquid  again. 
The  carbon  difficulty  has  always  attended  the  use  of  crude  and 
heavy  oils,  especially  when  these  have  an  asphaltic  base.  The 
base  remains  unconsumed,  and  when  an  engine  stops  and  cools 
it  becomes  glued  up  by  the  asphalte.  It  is  better  not  to  use 
such  oils  in  an  engine.  If  such  must  be  used  it  should,  if 
possible,  be  the  practice  to  run  the  engine  for  a  time,  before 
stopping,  with  paraffine  in  order  to  clear  away  any  varnish- 
like  deposit  before  allowing  the  engine  to  stop  and  cool.  See 
class  (e).  But  this  is  not  necessary  with  ordinary  crude  oils, 
such  as  are  used  in  class  (c).  This  class  (c)  is  merely  an  exten- 
sion of  class  (b)  and  includes  the  above  Hornsby  engine  of  which 
the  vaporizer  is  shown  in  Fig.  83  ;  the  Huston-Proctor  engine,  in 
which  a  small  vaporizing  chamber  is  attached  at  the  back  of 
the  cylinder  and  receives  the  spray  of  fuel  forced  in  through  a 
narrow  orifice  by  which  the  oil  is  atomized.  As  far  as 


272          LIQUID  FUEL  AND  ITS   APPARATUS 

possible  the  oil  in  this  class  of  engine  should  be  vaporized  as 
it  enters  and  not  allowed  to  fall  liquid  on  too  hot  a  surface,  by 
which  it  may  be  cracked  or  decomposed  with  formation  of 
solid  carbon. 

All  kinds  of  crude  oil  and  residual  oils  have  been  tried  in  the 


83.     HOBNSBY  OIL  ENGINE  VAPOBIZEB. 


Huston-Proctor  engine,  varying  in  sp.  gr.  from  0-86  to  0-96. 
A  special  Italian  residual  oil  with  15  to  25  per  cent,  of  tar 
was  tried  also,  and  in  no  case  was  there  any  gummy  or  sooty 
deposit. 

In  this  class  of  engine  the  oil  sprays  by  its  own  heavy  pressure. 
Fuel  consumptions  are  claimed  as  low  as  0-45  Ib.  per  b.h.p. 


THE   OIL  ENGINE 


273 


hour,  but  0-5  Ib.  should  usually  be  assumed.  In  the  Ruston 
engine  a  small  quantity  of  water  is  injected  into  the  cylinder 
at  each  suction  stroke.  In  the  Hornsby  engine  this  water 
injection  is  not  used.  The  use  of  water  has  its  advocates  and 
the  reverse.  In  its  favour  are  claimed  that  it  is  a  safeguard 
against  overheating  at  full  loads,  that  it  prevents  knocking 
from  over-hot  valves  or  piston,  and  obviates  risk  of  cylinder 
scoring  and  seizing  of  pistons. 

Class  (d) :  The  Diesel  engine  occupies  this   class  by  itself. 


Fig.  84.     ENLARGED  CROSS  SECTION  or  VAPORIZER. 


It  depends  for  its  working  upon  the  compression  of  a  charge 
of  pure  air  to  so  high  a  pressure — some  35  atmospheres  — 
that  oil  injected  into  this  air  will  be  ignited.  Since  the  air 
charge  has  a  pressure  of  about  500  pounds  per  sq.  in.,  the  air  by 
which  the  fuel  is  sprayed  into  this  charge  is  furnished  by  a  pump 
at  about  800  Ib.  pressure.  The  engine  is  best  started  by  com- 
pressed air,  a  store  of  which  is  maintained.  The  storage  vessels 
are  sent  out,  ready  charged,  with  the  engine,  and  serve  for 
starting  from  the  first,  and  the  air  pressure  is  carefully  main- 
tained so  to  avoid  the  inconvenience  of  hand  pumping  a  fresh 
store. 


274          LIQUID  FUEL  AND  ITS  APPARATUS 

The  thermal  efficiency  of  the  Diesel  engine  is  given  by  one 
maker  as  40-7  per  cent,  on  the  indicated  horse  power,  and  31  0 
per  cent,  on  the  brake  horse  power.  The  Author's  own  tests 
fully  corroborate  these  figures.  The  best  steam  engines  give 
similarly  22-0  per  cent,  and  20-5  per  cent,  with  superheated 
steam  at  300°C.=  572°F.  This  of  course  does  not  include  the 
boiler.  Producer  gas  engines  give  20  to  26  per  cent. 

Many  oil  engines  work  on  the  Otto  cycle,  which  is  a  four 
stroke  cycle,  but  in  many  Diesel  engines,  especially  for  marine 
work,  the  engine  drives  an  air  scavenging  pump  and  the  exhaust 
takes  place  by  a  ring  of  ports  uncovered  by  the  piston  and  the 
waste  gases  are  swept  out  by  a  scavenging  of  air,  and  the  engine 
is  then  run  on  the  two-stroke  cycle. 

The  use  of  liquid  fuel  in  the  Navy  has  naturally  led  up  to 
the  employment  of  the  oil  engine,  and  the  Diesel  engine,  by 
reason  of  its  economy,  has  become  the  accepted  type.  Its  oil 
consumption  at  full  load  is  about  0-44  Ib.  of  oil  per  b.h.p.  hour. 

Assuming  the  oil  to  have  a  thermal  capacity  of  19,320  B.Th.U. 
and  the  heat  equivalent  of  one  horse  power  to  be  2,544 
B.Th.U.,  an  engine  using  1  pound  of  oil  per  h.p.  hour  would 
have  an  efficiency  of  2,544  -f-  19,320  =  13-1  per  cent.  The 
efficiency  with  any  other  rate  of  fuel  consumption  would  be 
this  last  number  -;  fuel  consumption.  Thus  if  the  fuel  con- 
sumption were  0-4  Ib.  per  h.p.  hour,  the  efficiency  would  be 
32-0  per  cent,  and  this  may  be  attained  in  the  Diesel  engine. 

The  position  already  taken  by  the  Diesel  engine  in  marine 
work  is  already  good,  but  as  in  all  four-stroke  single  acting 
engines,  the  weight  is  great  for  the  power  developed,  and  the 
tendency  is  to  convert  it  into  a  two-stroke  engine  and  also  to 
make  it  double-acting.  This  of  course  demands  an  exhaust 
uncovered  by  the  piston  and  a  scavenging  charge  of  air  to 
sweep  out  the  exhaust  gas,  but  these  are  details  which  may 
pertain  to  all  engines  and  do  not  apply  to  the  question  of  the 
fuel  used  by  them,  and  need  not  here  be  further  considered. 

Class  (d),  the  Griffin  engine,  of  which  Fig.  85  shows  a  section 
of  the  vaporizer  of  a  9|"  X  10|"  X  4  cyl.  engine,  occupies  this 
class  of  heavy  oil-using  engines. 

It  is  based  on  the  claim  that  no  engine  can  satisfactorily 
use  an  oil  with  a  heavy  base,  particularly  an  asphaltic  base. 
In  it,  therefore,  is  embodied  an  exhaust  heated  external 
vaporizer.  This  is  first  heated  by  an  air  blown  flame,  and  serves 
to  vaporize  the  first  charge,  and  it  is  maintained  at  about  450°F. 
=232°C.,  by  the  subsequent  exhaust  gases.  The  oil  is  distilled 
but  not  cracked  ;  the  heavier  portions  remain  unaltered  and  are 
run  out  of  the  vaporizer  by  a  gravity  pipe.  The  Author  has 


THE   OIL  ENGINE  275 

seen  such  rejected  portion  placed  on  a  cold  iron  plate,  and  it 
became  a  hard  dry  varnish  at  once,  as  it  would  have  done 
inside  the  cold  engine  if  allowed  to  get  in. 

The  interior  of  the  Griffin  engine  remains  clear  of  all  deposit 
of  carbon  or  coke  or  asphalte.  There  is  always  found  some 
very  fine  ash  in  petroleum,  and  this  also  is  kept  out  of  the 
cylinder,  where  its  presence  would  produce  abrasion.  The  oil 
is  heated  in  the  supply  pipe  to  the  vaporizer,  as  is  also  the  air 
for  spraying  it  in.  This  facilitates  the  free  flow  of  the  oil,  and 
assists  in  fine  atomization. 

The  vaporizer,  Fig.  85,  has  an  outer  jacket  marked  lOfdia. 
in  this  size,  surrounding  an  inner  annular  chamber  7f  "  dia., 
which  in  turn  encircles  a  central  vaporizing  chamber  5J"  dia., 
into  which  the  fuel  is  sprayed.  The  exhaust  gases  from  the 
cylinder  traverse  the  annular  chamber.  Their  temperature  is 
a  maximum  of  550°E.  =  288°C.,  which  becomes  450°E.  —  232°C. 
in  the  annular  chamber.  Thus  the  fuel  is  vaporized,  not  gasi- 
fied, a  physical  and  not  a  chemical  change.  It  is  in  fact  merely 
a  fractional  distillation  which  leaves  the  undesirable  refuse  to 
be  run  out  of  the  still  as  tar  or  asphalte.  The  vaporizer  is  only 
at  atmospheric  pressure  ;  it  is  never  exposed  to  great  tempera- 
ture. 

All  the  air  required  in  the  cylinder  does  not  pass  through  the 
vaporizer.  Enough  passes  that  way  to  carry  in  the  charge  of 
oil  vapour  ;  the  remainder  is  admitted  by  a  separate  air  valve. 
Incidentally  this  engine  is  started  by  a  momentum  device,  the 
fly-wheel  having  a  friction  clutch  grip  on  the  shaft.  A  boy  can 
gradually  get  up  the  fly-wheel  of  a  40  h.p.  engine  to  a  sufficient 
speed  ;  it  is  then  gripped  to  the  shaft  and  finds  the  starting 
energy. 

Ignition  is  by  a  refractory  body  in  a  small  and  isolated  cavity 
communicating  with  the  combustion  chamber.  A  timing  valve 
may  be  supplied  if  required. 

The  oil  and  the  compressed  air  by  which  it  is  sprayed  into 
the  heated  vaporizer,  are  both  heated  so  as  to  render  spraying 
more  perfect.  The  temperature  of  the  vaporizer  is  less  than 
that  which  would  gasify  the  oil,  and  the  tar  is  left  behind  in 
place  of  going  forward  to  the  cylinder  and  doing  harm. 

The  incombustible  ash  sticks  to  the  side  of  the  vaporizer  and 
can  be  removed  by  a  wire  brush  when  the  engine  is  stopped. 

The  spray  injector,  which  also  serves  as  the  heating  blow- 
lamp, has  an  adjustable  inner  nozzle  through  which  comes  air 
at  20  Ib.  pressure.  Oil  flows  in  through  an  annular  chamber 
round  this  inner  nozzle,  and  is  pulverized  by  the  air  and 
vaporized  by  the  hot  chamber. 


276          LIQUID  FUEL  AND  ITS  APPARATUS 

Both  oil  and  air  are  supplied  at  20  Ib.  pressure,  the  oil  coming 
from  a  closed  tank  to  which  the  air  pressure  pump  has  a  con- 
nexion, and  the  supply  of  oil  is  regulated  by  a  governor  which 


controls  the  air  at  the  atomizer.  There  is  no  change  in  the 
richness  of  the  mixture  supplied  but  only  in  its  volume,  the 
air  and  the  oil  being  simultaneously  varied. 


THE   OIL  ENGINE  277 

The  engine  can  be  started  if  desirable  with  light  oils,  as 
petrol  and  electrical  ignition,  the  heavy  oil  being  turned  on 
when  the  vaporizer  has  become  hot.  This  avoids  the  use 
of  the  blow-lamp  heater  in  the  locality  of  inflammable 
vapours. 

It  should  be  added  that  for  each  1,000  feet  of  elevation  above 
sea  level  an  engine  ought  to  be  about  3  per  cent,  larger  owing  to 
the  rarefied  air.  For  a  number  of  engines  it  might  be  found 
cheaper  to  pump  air  to  them  at  a  pressure  of  one  absolute 
atmosphere,  so  that  with  this  compound  system  no  increase  of 
engine  size  need  be  made.  This  applies  to  all  oil  or  gas  engines 
when  worked  at  considerable  heights  above  sea  level. 

It  is  external  to  the  intention  of  this  book  to  afford 
more  than  an  outline  of  the  general  systems  of  using  liquid 
fuel  in  the  internal  combustion  engine,  its  general  mechan- 
ism, etc. 

For  details  of  the  legion  of  different  engines,  their  valve  sys- 
tems, sprays,  vaporizers,  the  Author  would  refer  his  readers  to 
the  books  of  Mr.  Dugald  Clerk,  the  late  Bryan  Donkin  and  the 
catalogues  of  makers. 

As  the  liquid  fuel  engine  is  improved,  and  its  operation  made 
more  and  more  certain,  so  will  its  superior  thermal  efficiency 
bring  it  into  wider  use.  There  appears  to  be  no  immediate 
prospect  of  a  direct  oil  fuel  turbine  engine,  and  all  existing 
engines  are  of  the  reciprocating  type,  which  steam  turbine  makers 
have  endeavoured  with  so  much  success  to  put  out  of  use  for 
steam  using.  But  the  turbine  runs  too  fast  to  suit  the  propeller 
and  this  is  all  in  favour  of  the  reciprocating  oil  engine.  At 
present,  even  the  Diesel  engine  must  be  run  on  selected  fuel  as 
regards  freedom  from  asphalte,  etc.  Such  oils  with  an  asphaltic 
base  which  might  be  rejected  to  the  extent  of  15  per  cent,  by  the 
Griffin  engine  would  be  unsuitable  at  sea  even  if  their  unde- 
sirable elements  were  rejected  by  the  engine,  for  no  shipowner 
wants  to  carry  the  excess  of  fuel  that  this  implies.  On  land, 
therefore,  any  fuel  can  be  used  in  some  engines  ;  at  sea,  liquid 
fuel  must  be  selected,  except  for  short  journeys.  The  ability 
to  burn  any  fuel  under  boilers  in  high  temperature  refrac- 
tory furnaces  will  do  much  to  preserve  steam  power  against 
the  inroads  of  the  more  highly  efficient  internal  combustion 
engine.  The  near  future  will  see  many  oil  engines  in  marine 
work. 

It  will  be  noted  that  essentially  the  method  of  using  oil 
in  the  internal  combustion  engine  is  by  spraying  or  atomizing 
the  oil  into  the  air  with  which  it  is  to  burn,  or  by  spraying  it 
into  a  vaporizer  in  which  it  is  evaporated,  and  whence  it  passes 


278          LIQUID  FUEL  AND  ITS  APPARATUS 

into  the  cylinder  as  a  vapour.  Petrol  vaporizes  at  ordinary 
atmospheric  temperature.  Heavy  oils  must  have  the  high 
temperature  vaporizer  of  the  Griffin  engine,  or  be  directly 
ignited  and  burned  in  the  highly  heated  chambers  of  other 
types  of  engine  or  burned  in  the  "  red  hot  "  air  of  the  Diesel 
high  compression  engine. 


Part   III 
TABLES 


TABLES 


281 


TABLE  I.     Composition  of  Crude  Oils. 


Name. 

C. 

H. 

0. 

Sp.  G. 

Per  deg.  C. 
Coeff.  of 
Expansion. 

B.Th.U. 
Cal. 

Capacity. 

Heavy  Virginia 
„      Ohio       .      . 
„      Pa..        .      . 
Gas  coal  oil 
E.  Galician 
W.  Galician       .      . 
Java       .... 
Caucasian 
Rangoon 

83-5 

84-2 
84-9 
82 
82-2 
85-3 
87-1 
85-3 
83-8 

13-3 
13-1 
13-7 
7-6 
12-1 
12-6 
12-0 
11-6 
12-7 

3-2 

2-7 
1-4 
10-4 
5-7 
2-1 
0-9 
5-1 
3-5 

•873 

•887 
•886 
1-044 
-870 
•885 
-923 
-9405 
•875 

•00072 
•000748 
•000721 
•00744? 
•000813 
•000775 
•000764 
•000696 
•000774 

10,180 
10,399 
10,672 
8,916 
10,005 
10,231 
10,831 

TABLE  II.     Calorific  Capacity  of  Liquid  Fuel  Oils. 


Locality. 

Fuel 

Sp.  G. 
0°C. 

C. 

H. 

0. 

Calorific 
Capacity. 

Actual 
Calories 

Calcula- 
ted  Cal. 

Russian   . 

»         • 
Caucasus  . 
American 
Scotcji 

Pet.  refuse    . 
Astatki    .      . 
Heavy  crude 
Solid  residuum 
B.F.  Oil  .      . 

928 
900 
938 

920 

87-10 
84-94 
86-60 
97-855 
83-64 

11-7 
13-96 
12-30 
0-489 
10-59 

1-2 
1-2 
1-1 
1-196 
9-458 

10,340 
11,800 
8,057 
10,328 

11,018 
11,626 
11,200 

TABLE  III.     Coefficient  of  Expansion  of  Crude  Oils. 


Sp.  G.x  1,000. 

Coefficient  of 
Expansion  of  Crude 
Oil  x  1,000,000 
Dr.  Engler. 

Pennsylvania     

816 

840 

Canada    

828 

843 

Alsace     

829 

843 

Virginia  

841 

839 

Alsace     
Wallachia     

861 
862 

858 
808 

E.  Galicia     

870 

813 

Rangoon       

875 

774 

Caucasus       

882 

817 

W.  Galicia    

885 

775 

Ohio  

887 

748 

Baku       

899 

784 

Hanover  (Odesse)    

892 

772 

Pechelbronn       

892 

792 

Wallachia     
Hanover  (Oberg)     

901 
944 

748 
662 

Hanover  (\Viesse)    

955 

647 

Heavy  viscous  oils  0-0007  to  -00072  between  20°  and  78°C.  =68 
172-4°F.  containing  paraffin  and  solid  below  20°  =0-0075  to  -00081. 


to 


282          LIQUID  FUEL  AND   ITS   APPARATUS 

TABLE  V.— THE  PROPERTIES  OF 


Required  to  burn 

Nominal  tern 

one  unit. 

combu 

Name. 

Sym- 
bol. 

Den- 
sity 
H  =  l 

Mole- 
cular 
Weight 

Lb. 

per 
cubic 
feet. 

Cubic 
ft. 
per 
Ib. 

Grams 
per 
Litre. 

Litres 
per 
Gram. 

Weight. 

Volume. 

Air. 

Air.     Oxy 

Air. 

Oxy 

F°. 

C°. 

gen. 

gen. 

Air  

(023) 

\  N7B  V 

14-44 

08073 

12-385 

1-29318 

•773 

Carbon,  C— 
Amorphous     . 

)        76  i 

U,  J 

— 

-{ 

to  CO    I 
to  C02  ) 

— 

— 

— 

— 

2673-5 
4938 

1485 

2753 

Vapour      .     . 

— 

12 

— 

06696 

14-930 

1-0727 

•932 

— 

— 

9-54 

2-00 

6955 

3846 

Carbon  Dioxide      . 

C02 

22 

44 

12344 

8-147 

•967 

•508 

— 

— 

— 

— 

— 

— 

Carbonic  Oxide 

CO 

14 

28 

07817 

12-80 

1-2515 

•800 

2-484 

•571 

2-3S1 

•500 

3494 

1923 

( 

Wate: 

Hydrogen   . 

H2 

1 

2 

00559 

178-83 

•08981 

11-16 

34-785 

8-000 

2-39 

•500 

4813 

2674 

Oxygen       .     .     . 

02 

16 

32 

08926 

11-203 

1-4298 

•699 

_ 

Nitrogen     .     .     . 

N, 

14 

28 

07845 

12-763 

1-25616 

•796 

— 

— 

— 

— 

— 

— 

Steam    .... 

H20 

9 

18 

05022 

19-912 

•8047 

•1242 

— 

— 

— 

— 

— 

— 

Acetylene    .     .     . 

C2H2 

13 

26 

•07267 

13-456 

1-190 

•840 

13-378 

3-077 

11-93 

2-500 

6120 

3400 

Benzine. 

C6H6 

39 

78 

•208 

4-808 

3-333 

•303 

13-378 

3-077 

35-80 

7-500 

5022 

2790 

| 

Ethylene     .     .     . 

C2H4 

14 

28 

•07814 

12-797 

1-2519 

•799 

14-903|3-428 

14-30 

3-000     5400 

3000 

Ethane  .... 

C2H6 

15 

30 

•08565 

11-950 

1-3415 

•746 

16-484  3-733 

16-70 

3-500     4354 

2419 

Methane      .     .     . 

CH4 

8 

16 

•04466 

22-391 

•7155 

1-397 

17-392(4-000 

9-54 

2-000     4036 

2245 

Ethyl     .... 

C2H60 

23 

46 

•12857 

7-775 

2-061 

•287 

9-074 

2-037 

14-30 

3-000 

4630 

2573 

Methyl  .... 

CH4O 

16 

32 

•08926 

11-203 

1-4208 

•699 

6-521 

1-500 

7-15 

1-500 

4183 

2325 

Cyanogen    .     .     . 

C2N2 

26 

52 

•1453 

6-88 

2-338 

•427 

5-348 

1-23 

9-54 

2-000     6099 

3388 

Glycerine     . 

C3H803 

— 

92 

— 

— 

— 

— 

18-148 

4-174 

16-70 

3-500     4000 

2222 

Blast  Furnace  Gas 

/      1  r\f\ 

.OO       ^ 

FCO]27  N65  (C02)6 
H2      .     .     .     . 

— 

14  + 

— 

•079 

12-65 

1-2515 

•800 

j  *1UU 

\-721 

•2.2,    } 
•166  J 

•82 

•164     2160 

' 

1200 

ProducerGas  [C0]25 
(Sundry)r5-[C02]2.5 

— 

14  + 

— 

•079 

12-65 

1-2515 

•800 

(•99 

\-721 

•21    } 
•166  j 

— 

(3440 
I  2160 

1910) 
1200  J 

[CH4]2,  N69   .      . 

Water  Gas  |CO]76, 

[CH412,  [Sundry]7-5 
(C02)10  N2.5  .      . 

— 

8  + 

— 

•045 

22-5 

•726 

1-40 

3-878 

•788 

— 

— 

4850 

2700 

Coal  Gas,  H8[CH4]57 

[C0]15  N4)  (Sun- 

dry)^      .      .      . 

— 

4-7 

— 

•032 

31-6 

•516 

1-975 

13-89 

2-81 

6-16 

1-23        4500 

2500 

Natural  Gas(CH4)90) 

N6,  Sundry4  .     . 

— 

8 

—       -045 

22-5 

1-726 

1-40 

15-00 

3-06 

— 

—        4200 

2333 

NOTE. — Gases  expand  by  heat  to  the  extent  of    ^  of  their  bulk  at  0°C.  for  each  degree  Centigrade,  or  jgj^ 
The  specific  heat  of  gases  varies  with  the  temp3rature,  being  greater  for  higher  temperatures.     At   the 
Lechatelier  therefore  gives  a  formula  for  specific  he.it    Cp  =  6-5  +aT,  where   T   is  the  absolute  temperature 
This  has  an  important  bearing  on  the  theory  of  the  gas  engine. 


TABLES 


283 


GASES  (KEMPE'S  YEAR  BOOK). 


perature  of 

Heat  generated  by  combustion  of  one 

Heat  of 

Specific  Heat. 

stion. 

formation  at 

15°C.  per 

Oxygen. 

Lb. 

Cub.  ft. 

Gram. 

Litre. 

Molecule. 

Molecule. 

Water  =1. 

Fo 

C° 

B.Th.U. 

B.Th.U. 

Cal. 

Cal. 

Cal. 

Cal. 

Liquid. 

Constant. 

^ 

Pressure 

Volume. 

— 

— 

— 

— 

— 

— 

— 

— 

— 

•2375 

•1686 

7725 

4292 

4415-9 

_ 

2-4533 



29-44 

2-841     \ 

•2415 

18440 

10226 

14647 



8-1375 

— 

97-65 

3-343     J 

25752 

14290 

20461 

1370-5 

11-3675 

12-193 

136-41 

f  —  3S-762     \ 
\  —42-13       ; 

— 

•285 

— 

68-20*     ) 

— 

— 

— 

— 

— 

— 

_ 

94-313 

— 

216-9 

•171 

97-65a     j 

perun 
12892 

.of  C.= 
7144 

10232  ) 
4383    | 

(  799-3 
\  342-5 

f  5-684 
t  2-436 

f  7-105) 
\  3-047  j" 

68-2 

i      26-13       x 
[      29-42       J 

— 

•245 

'•173 

Vapo 
12108 

ur)       ( 
6727  | 

52290 
at  32°F. 
62100 

(293 
\347 

f  29-15 
\  34-50 

f  2-612 
\  3-091 

(  58-3  gas    \ 
\  69-0  liq.     L 
1  70-4  solid  j 

— 

- 

3-410 

•234146 

Water  Liquid. 

— 

— 

—               — 



— 

— 

— 

— 

•217 

•15481 

— 

— 

—              — 



— 

— 

— 

— 

•244 

•173 

l 

Solid  =  70-4  \ 

1  1-0  liq.      \ 

—  - 

— 

— 

— 

— 

— 

Liq.  =69-0  \ 
Gas   =58-3J 

perH2 

-504 
(  Solid       j 

•479 

•370 

20340 

11300 

21856 

1624 

12-142 

14-46 

315-7 

—58-1 

— 

•373 

— 

16830 

9350  | 

18094    \ 
17930    j 

3764 

J  10-052  ) 
\    9-960   J 

33-496 

f  784-1  gas 
I  776-9  liq. 

(—1-8  sol.  \ 
-  4-1  liq. 
(—11  -3  gas) 

•43602 

•3754 

•350 

16886 

9381 

21927 

1744 

12-182 

15-250 

341-1 

—14-8 

— 

•404 

•332 

14848 

8249 

22338 

1912 

12-410 

16-641 

372-3 

23-3 

— 

— 

— 

14348 

7971 

24017 

1073 

13-343 

,  9-547 

213-5 

18-9 

— 

•593 

•468 

125S3 

6690 

12744 

1639-1 

7-080 

14-54 

325-7 

f      59-8  gas  ) 
\     69-9  liq.  } 

f  -60  liq.     I 
I  -50  gas     J 

•451 

•320 

10216 

5675 

9596 

856-5 

5-331 

7-627 

170-6 

(      53-3  gas  ) 
\     61-7  liq.  > 

f  -66  liq.     ) 
I  -46  gas     ) 

— 

— 

18222 

10215 

9086 

1320-6 

5-048 

12-02 

262-5 

f—  73-9  gas  I 
\  —68-5  liq.  } 

— 

— 

— 

8078 

4488 

7770 

— 

4-317 

— 

397-2 

f    161-7  liq.) 
\    165-6  sol.  J 

— 

— 

— 

4500 

2500  | 

1223  to 
1237 

96-7} 

97-8} 

•700 

•900 

— 

— 

— 

— 

— 

4590 

2500  \ 

1265  to  ) 

100  to 

f  -773  to 

i      -9674  to 

2530      / 

200 

1  1-370 

1      1-713 

— 

— 

— 



f 

4230  to 

330  to 

(  2-35  to 

3-00  to  ) 

__ 

\ 

5458 

700 

\3-03 

6-33       J 

— 

— 

21400 

685 

11-9 

6-099 

— 

— 

— 

— 

— 

— 

— 

24444 

1100 

13-58 

10-0 

— 

— 

— 

— 

— 

1  From  Graphite.        2  From  Amorphous  Carbon.        3  From  Diamond.        4  From  Carbonic  Oxide, 
of  their  bulk  at  32°F.  for  each  degree  F.. 

absolute  zero  the  values  of  the  molecular  heat  of  all  gases  seems  to  converge  at  6-5  for  constant  pressure  values. 
dpL  and  a  is  a  co-efficient  greater  according  to  the  complexity  of  the  molecule.     For  values  of  a  see  table, 
(T=  Temperature  Centigrade.) 


284          LIQUID  FUEL  AND   ITS  APPARATUS 

TABLE  IV.     Calorific  Power  of  Crude  Oil. 


Sp.  Gr. 

Cal.  Capacity. 

W.  Virginia  

•873 

10190  cals 

Oil  Creek,  Pa  

•816 

9963 

•923 

10831 

Baku       
E.  Galicia    
W.  Galicia  

•884 
•870 
•885 
•786 

11460 
10005 
10231 
10121 

Schwabweiler  (Alsace)        .... 

•861 

10458 

TABLE  VI.     Temperature. 


C°. 

F°. 

Red  heat  in  daylight  
Iron  red  in  dark  .  . 

577° 
400° 

1070° 

752° 

Bessemer  furnace  

2205° 

4000° 

Common  fire  
Copper  melts  .  
Lead 

595° 
1232° 
316° 

1100° 

2160° 
600° 

Tin 

215° 

420° 

Grey  cast-iron  melts  
White  „  „  „  
Carbon  vaporizes  .  .  . 

1100° 
1050° 
3600° 

2012° 
1922° 
6512° 

TABLE  VII.     Specific  Heats  of  Gases. 


Const.  Vol. 

Const.  Pressure. 

Air                      ....... 

•168 

•2375 

•1548 

•217 

•173 

•244 

2-4146 

3-410 

•173 

•245 

•171 

•216 

•468 

•593 

Olefiant  gas    C2H4       .      . 

•332 

•404 

Steam    H^O       

•370 

•479 

Blast  furnace  sas 

•163 

•228 

Steam  boiler  furnace  gas. 

•171 

•240 

.      •] 

298 

.      .      .      .      •] 

138 

Steel   
Brick 

.      .      .      .      •] 

.f 

17 
$41 

TABLES 


285 


TABLE  VIII.     Equivalents. 

Cal  ...........  3-968  B.Th.U. 

B.Th.U  .....      .....  0-252  CaJ. 

°C  ............  f°F. 

°F  ............  |°C. 

°C  ............  t°R. 

°R  ............  |0C. 

kilog  ...........  2-204 

pound       .........  0-453  k. 

1  B.Th.U  ..........  772  ft.  pounds  (old). 

„  .........  778   „  „      (new) 

1  calorie      .........  423-55  k.m.  (old). 

.........  426-84     „       (new). 

772  ft.  p.  per  1°F  .......  1389-6  ft.  p.  per  1°C. 


778 

423-55  k.m. 

426-84  k.m. 


1400-4 

3063-54  ft.  Ib. 

3087-3  ft.  Ib. 

107-78  k.m. 

7-231  ft.  Ib. 

2  Ib.  per  yard  nearly. 


B.Th.U 

k.m 

k.  per  linear  m 

B.Th.U.  per  foot3    ......  9  Cal.  per  m.3      „ 

.........      .  32-2  ft.  per  sec.2 

g        ......      .....  9-8117  m.  per  sec.2 

1  B.Th.U.  per  ft.2       ......  2-713  cal.  per  m.2 

1  „         Ib  .......  0-556  cal.  per  kilo. 

1  kilo,  per  cm.2     .....      .      .  14-2  Ib.  per  sq.  inch. 

1  Ib.  per  sq.  inch        ......  0-0703  kilo,  per  cm.2 

1  metre-kilo  .........  7-231  ft.  pounds. 

1  ft.  pound       ........  0-138  metre-kilo. 


TABLE  IX.     Properties  of  Carbon  Calorifically, 


Calories  per 

British 
Thermal  Units. 

Temperature 
of  Com- 
bustion. 

Mole- 
cule. 

Litre. 

Gram. 

Per 
Cubic  Ft. 

Per 
Pound 

In  Air. 

Amorphous  to  CO    . 

29-44 

— 

2-453 



4416 

1485° 

2705° 

„  CO2  . 

97-65 

— 

8-1375 

14647 

2753° 

4988° 

Vapour  to  CO    .      . 

68-20 

6-096 

5-864 

685-25 

10231 

3540° 

6373° 

C02  .      . 

136-41 

12-193 

11-3675 

1370-50 

20461 

2846° 

6955° 

CO=2^1b.  to  CO2     . 

68-20 

3-046 

5-684 

342-50 

10232 

1923° 

3494° 

CO  =  lib.  toCO2     . 

29-23 

3-048 

2-436 

342-50 

4384 

1923°  3494° 

Hydrogen  to  H2O  gas 

58-30 

2-612 

29-15 

293-00 

52290  2513°|4554° 

,,         H2O  water 

69-00 

3-091 

34-50 

347-00 

62100  2974°  5385° 

The  important  figures  for  practice  are  in  black  type. 


286          LIQUID  FUEL  AND  ITS   APPARATUS 


TABLE  X. 

TENSION   (f.)    OF  AQUEOUS  VAPOUR    IN    MM.    OF    MERCURY    PER    DEGREE 
CENTIGRADE  (T. )°  AND  GRAMS  (g.)  PER  CUBIC  METRE  OF  SATURATED  AIR. 


T°. 

g. 

f. 

T°. 

g' 

f. 

rpo 

g. 

f. 

0 



4-5 

11 

10-0 

9-7 

22 

19-3 

19-6 

1 

— 

4-9 

12 

10-6 

10-4 

23 

20-4 

20-9 

2 

— 

5-2 

13 

11-3 

11-1 

24 

21-5 

22-2 

3 

— 

5-6 

14 

12-0 

11-9 

25 

22-9 

23-5 

4 

— 

6-0 

15 

12-8 

12-7 

26 

24-2 

25-0 

5 

6-8 

6-5 

16 

13-6 

13-5 

27 

25-6 

26-5 

6 

7-3 

6-9 

17 

14-5 

14-4 

28 

27-0 

28-1 

7 

7-7 

7-4 

18 

15-1 

15-3 

29 

28-6 

29-8 

8 

8-1 

8-0 

19 

16-2 

16-3 

30 

29-2 

31-6 

9 

8-8 

8-5 

20 

17-2 

17-4 

— 

— 

— 

10 

9-4 

9-1 

21 

18-2 

18-5 

— 

— 

— 

TABLE  XI. 


BELATIVE  VALUE  OF  COAL  AND  OIL, 
FUEL  ACCOUNT  ALONE  CONSIDERED. 


BELATIVE  VALUE  OF  COAL  AND  OIL,  ALL 
ASCERTAINED  ECONOMIES  CONSIDERED. 


,r  Barrel  at                Coal  per  Ton  at                      Coal  per  Ton  at 

0-20 

$0-74 

$0-65 

0-30 

1-12 

0-98 

0-40 

1-49 

1-30 

0-50 

1-86 

1-63 

0-60 

2-24 

1-96 

0-70 

2-61 

2-28 

0-80 

2-98 

2-61 

0-90 

3-35 

2-93 

1-00 

3-73 

3-26 

•10 

4-10 

3-59 

•20 

4-47 

3-91 

•30 

4-85 

4-24 

•40 

5-22 

4-56 

•50 

5-59 

4-89 

•60 

5-97 

5-22 

•70 

6-34 

5-54 

•80 

6-71 

5-87 

1-90 

7-08 

6-19 

2-00 

7-45 

6-52 

1  dollar  =48  pence, 

approximately. 

TABLE 

XII.     Russian  and  Pennsylvanian  Oils. 

Penn- 

Russian. 

sylvanian. 

Light. 

Heavy. 

Refuse. 

Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

Carbon       . 
Hydrogen        

84-9 
13-7 

86-3 
13-6 

86-6 
12-3 

87-1 
11-7 

Oxvfifsn 

1-4 

0-1 

!•! 

1-2 

Sp.  Gr.  at  32°F  
B.Th.  Units     

100-00 

0-886 
19,210 

100-00 

0-884 

22,628 

100-00 

0-938 
19,440 

100-00 

0-928 
19,260 

Evaporation  at  8  atmospheres  . 

16-2 

17-4 

16-4 

16-2 

TABLES 


287 


TABLE  XIII.     Petroleum  Refuse. 

Specific  Gravity  and  Weight  per  cubic  foot,  at  various  temperatures. 
Water  =  1-0000  specific  gravity,  at  17£°  Cent.  =63^°  Fahr. 


Temperature. 

Specific 
Gravity. 

Weight  in  Ib. 
per  cubic  foot. 

Centigrade. 

Reaumur. 

Fahrenheit. 

0 

0-0 

32-0 

0-9110 

56-61 

1 

0-8 

33-8 

0-9103 

56-55 

2 
3 

1-6 
2-4 

35-6 
37-4 

0-9097 
0-9091 

I      56-50 

4 

3-2 

39-2 

0-9085 

56-42 

5 

6 

4-0 

4-8 

41-0 

42-8 

0-9078 
0-9072 

56-36 

7 

5-6 

44-6 

0-9066 

\ 

8 

6-4 

46-4 

0-9060 

y      56-30  . 

9 

7-2 

48-2 

0-9053 

56-20 

10 
11 

8-0 
8-8 

50-0 
51-8 

0-9047 
0-9041 

56-14 

12 

9-6 

53-6 

0-9034 

56-11 

13 
14 

10-4 
11-2 

55-4 
57-2 

0-9028 
0-9022 

1      56-05 

15 

12-0 

59-0 

0-9016 

55-99 

16 

12-8 

60-8 

0-9009 

I       *t^'<)2, 

17 

13-6 

62-6 

0-9003 

V            *  )»  )    .  '_ 

18 

14-4 

64-4 

0-8997 

KK.QA 

19 

15-2 

66-2 

0-8991 

[•         OO  o*t 

20 

16-0 

68-0 

0-8984 

55-81 

21 

22 

16-8 
17-6 

69-8 
71-6 

0-8978 
0-8972 

1      55-74 

23 

18-4 

73-4 

0-8965 

55-68 

24 
25 

19-2 
20-0 

75-2 

77-0 

0-8959 
0-8953 

I      55-62 

26 

27 

20-8 
21-6 

78-8 
80-6 

0-8947 
0-8940 

I      55-55 

28 

22-4 

82-4 

0-8934 

55-48 

29 
30 

23-2 
24-0 

84-2 
86-0 

0-8928 
0-8922 

I      55-43 

31 

24-8 

87-8 

0-8915 

55-37 

32 
33 

25-6 
26-4 

89-6 
91-4 

0-8909 
0-8903 

j      55-30 

34 

35 

27-2 
28-0 

93-2 
95-0 

0-8896 
0-8890 

55-24 

288          LIQUID  FUEL  AND  ITS  APPARATUS 

TABLE  XIV.     Conversion  Table  for  Degrees  Baume. 


Degrees 
Baume. 

Degrees 
Sp.  Gr. 

Lb.  in  1  gal. 
(American). 

Degrees 
Baume1. 

Degrees 
Sp.  Gr. 

Lb.  in  1  gal. 
(American). 

10 

1-0000 

8-33 

43 

•8092 

6-74 

11 

•9929 

8-27 

44 

•8045 

6-70 

12 

•9859 

8-21 

45 

•8000 

6-66 

13 

•9790 

8-16 

46 

•7954 

6-63 

14 

•8722 

8-10 

47 

•7909 

6-59 

15 

•9655 

8-04 

48 

•7865 

6-55 

16 

•9589 

7-99 

49 

•7821 

6-52 

17 

•9523 

7-93 

50 

•7777 

6-48 

18 

•9459 

7-88 

51 

•7734 

6-44 

19 

•9395 

7-83 

52 

•7692 

6-41 

20 

•9333 

7-78 

53 

•7650 

6-37 

21 

•9271 

7-72 

54 

•7608 

6-34 

22 

•9210 

7-67 

55 

•7567 

6-30 

23 

•9150 

7-62 

56 

•7526 

6-27 

24 

•9090 

7-57 

57 

•7486 

6-24 

25 

•9032 

7-53 

58 

•7446 

6-20 

26 

•8974 

7-48 

59 

•7407 

6-17 

27 

•8917 

7-43 

60 

•7368 

6-14 

28 

•8860 

7-38 

61 

•7329 

6-11 

29 

•8805 

7-34 

62 

•7290 

6-07 

30 

•8750 

7-29 

63 

•7253 

6-04 

31 

•8695 

7-24 

64 

•7216 

6-01 

32 

•8641 

7-20 

65 

•7179 

5-98 

33 

•8588 

7-15 

66 

•7142 

5-95 

34 

•8536 

7-11 

67 

•7106 

5-92 

35 

•8484 

7-07 

68 

•7070 

5-89 

36 

•8433 

7-03 

69 

•7035 

5-86 

37 

•8383 

6-98 

70 

•7000 

5-83 

38 

•8333 

6-94 

75 

•6829 

5-69 

39 

•8284 

6-90 

80 

•6666 

5-55 

40 

•8235 

6-86 

85 

•6511 

5-42 

41 

•8187 

6-82 

90 

•6363 

5-30 

42 

•8139 

6-78 

95 

•6222 

5-18 

The  Sp.  Gr.  x  10  =  weight  in  pounds  per  imperial  gallon. 


TABLE  XV.     Of  the  Heat  of  Combustion  and  Air  consumed  by  various 

Fuels. 


Fuel. 

Oxygen 
per  pound 
of  fuel. 

Air  per  pound  of 
fuel. 

Total  heat 
per  Ib.  of 
fuel. 

Evapora- 
tion from 
and  at 
212°F. 

Hydrogen     . 
Carbon  to  COa  • 
Average  Coal     . 
Coke        .      .      . 
Petroleum    . 

Ib. 
8-0 
2-66 
2-45 
2-49 
3-29 

Ib. 
34-8 
11-6 

10-7 
10-81 
14-33 

Cubic  ft. 
457 
152 
140 
142 
188 

B.Th.U. 
62,100 
14,647 
14,700 
13,548 
20,411 

Ib. 
62-4 
15-0 
15-22 
14-02 
21-13 

TABLES 


289 


TABLE  XVI.     Theoretical  Flame  Temperatures. 


In  Air. 


Centigrade. 

Fahrenheit. 

C  to  CO      
C  to  CO2    
CO  to  CO2             •                 ... 

1485° 
2753 
1923 

2705° 
4988 
3494 

Hydrogen    
Marsh  gas,  CH4     
Olefiant  gas    C2H4 

2513 
2245 
3000 

4554 
4036 
5400 

Acetylene,  C2H2    

3400 

6120 

Benzine    C«Hg 

2790 

5022 

Producer  gas           

1200 

2160 

Coal  gas      

2700 
2400 

4860 
4320 

Naphthalene                 

2730 

4914 

Wood     

2280 

4104 

Lignite  (dry)                       . 

1200 

2160 

Coal  (bituminous). 

1500 

2700 

TABLE  XVII.     Weight  and  Volume  of  Gases. 


Weight. 

Volume. 

Per  cubic 

Per  cubic 

Per  kilogram 

Per  pound 

metre  in 

foot  in 

in  cubic 

in  cubic 

kilograms. 

pounds. 

metres. 

feet. 

Air    

1-29318 

0-08073 

0-773 

12-385 

Nitrogen      .... 

1-25616 

0-07845 

0-796 

12-763 

Oxygen  

1-4298 

0-08926 

0-699 

11-203 

Hydrogen     .... 

0-08961 

0-00559 

11-160 

178-83 

Carbonic  acid,  CO2 

1-9666 

0-12344 

0-508 

8-147 

Carbonic  oxide,  CO     . 

1-2515 

0-07817 

0-800 

12-800 

Carbon  vapour,  C   . 

1-0727 

0-06696 

0-932 

14-930 

Aqueous  vapour,  H2O  . 

0-8047 

0-05022 

1-242 

19-912 

Ethylene,  C2H4 

1-2519 

0-07814 

0-799 

12-797 

Methane,  CH4  . 

0-7155 

0-04466 

1-397 

22-391 

Acetylene,  C2H2 

1-1900 

0-07428 

0-840 

13-456 

Benzine,  CfiH6  . 

3-3333 

0-208 

0-303 

4-808 

Ethane,  C2H6    .      .      . 

1-3415 

0-08565 

0-746 

11-950 

290         LIQUID  FUEL  AND  ITS  APPARATUS 


tiq 


C5  O5  FH  O 
CD  U5  00  »O 
CD  FH  FH  CO 
O5  ^  CO  ^ 
00  »0  CM  CM 
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CO  OO  FH  »O 
05  ^  05  00 

CO  Th  FH  CD 
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•CD  CO  »O  Cp     cp 
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>CO  CO  t^-O  O  CM 

•  cp  cp  »o  cp  cp  •«* 

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TABLES 


291 


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S 
•& 

« 

S 

2 


•ss 


•g  g  3 


.  00  O5  CO  pH 
£  t^-  CO  t^-  t^ 


00  O5  IO  CO 
Tt<  l>  OO   »O 


(N  O  O 
<N  <M  <N 


.  CO  t-  00  (M 

5  CO  (M  CO  CO 

•     t>  O  i-    QO 


w 


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PH 


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00 


<  c    «    t- 

00  CO  00  CO 


1  co  -<*  co  co  o 

O  CO  00  CO  <M  CO 

^Qp  CO  Oi  Oi  CO 

02  o  o  o  o  I-H 


292         LIQUID  FUEL  AND  ITS  APPARATUS 


TABLE  XXI.     Ignition  Point  of  Gases  (Mayer  and  Munoh\ 

Marsh  gas,  CH4 *667°C. 

Ethane,  C2H4 616 

Propane,  C3H8 547 

Acetylene,  C2H2 580 

Propylene,  C3H6 504 


TABLE  XXII. 

Kilos  per  square  metre  x  '2048  =pounds  per  square  foot. 
Pounds  per  square  foot  x  4-884=  kilos,  per  square  metre. 
Kilos,  per  square  cm.  x  14-223  =  pounds  per  square  inch. 
Pounds  per  square  inch  X  -0703  =  kilos,  per  square  cm. 
Evaporation  from  16°C.  at  12  kilos,  x  0-8222  =  evaporation  from  and 

at  100°C.  =  212°F. 
Evaporation  from  and  at  100°C.  =  212°F.  x  1-216  =  evaporation  from 

16°C.  =  61°F.  at  12  kilos. 
Metres  x  3-281  =  feet. 
Square  metres  x  10-764  =  square  feet. 
Feet  x  0-3048  =  metres. 
Square  feet  X  0-9308  =  square  metres. 
Gallons  X  4-546  =  litres. 
Litres  X  0-21998  =  gallons. 
Cubic    inches  X  16-386  =  cubic  cm. 
Cubic  cm.  x  0-061027  =  cubic  inches. 
Gallons  (Imp.)  x  1-2012  =  American  gallons. 
American  gallons  X  0-83226  =  English  Imp.  gallons. 
American  gallons  x  3-784  =  litres. 
Litres  x  0-2642=  American  gallons. 
Inches  water  gauge  x  25-4  =  millimetres  water  gauge. 
Imp.  gallons  x  0-1606  =  cubic  feet. 
Cubic  feet  x  6-288  =  gallons. 
Kilos  per  metre  x  2-015  =  pounds  per  yard. 
Pounds  per  yard  x  0-4962  =  kilos,  per  metre. 
Calories  per  M.3  x  0-1121  =  B.Th.U.  per  ft.3 
B.Th.U.  per  ft.3  x  8-92  =  cal.  per  M.3 
Calories  per  M.2  x  0-3686  =  B.Th.U.  per  ft.* 
B.Th.U.  per  ft.*  x  2-713  =  cal.  per  Metres. 


TABLES 


293 


TABLE  XXIII.     To  determine  Temperature  by  Fusion  of  Metals. 


Substance. 

Temp. 
Fahr. 

Substance. 

Temp. 
Fahr. 

Substance. 

Temp. 
Fahr. 

Spermaceti  . 
Wax-  white  . 
Sulphur  . 
Tin    ... 
Bismuth 
Copper   . 

120 
154 
239 
448 
512 
2,003 

Lead    .      . 
Zinc 
Antimony. 
Aluminium 
Brass   . 

619 
754 
815 
1,180 
1,742 

Silver,  pure 
Gold  coin  . 
Iron,  cast  . 
Steel  .  . 
Wrought  iron 

1,851 
2,128 
2,074 
2,550 
2,911 

TABLE  XXIV.  Volume  and  Weight  of  Dry  Air  at  Different  Temperatures 
under  a  Constant  Atmospheric  Pressure  of  29-92  in.  of  Mercury, 
the  Volume  at  32  deg.  Fahr.  being  1. 


Temperature. 
Degrees 
Fahrenheit. 

Volume. 

Weight  of 
a  Cubic  Foot 
inlb. 

Temperature  . 
Degrees 
Fahrenheit. 

Volume. 

Weight  of 
a  Cubic  Foot 
inlb. 

0 

•935 

•0864 

212 

1-367 

•0591 

12 

•960 

•0842 

230 

1-404 

•0575 

22 

•980 

•0824 

250 

1-444 

•0559 

32 

1-000 

•0807 

275 

1-495 

•0540 

42 

1-020 

•0791 

300 

1-546 

•0522 

52 

1-041 

•0776 

325 

1-597 

•0506 

62 

1-061 

•0761 

350 

1-648 

•0490 

72 

1-082 

•0747 

375 

1-689 

•0477 

82 

1-102 

•0733 

400 

1-750 

•0461 

92 

1-122 

•0720 

450 

1-852 

•0436 

102 

1-143 

•0707 

500 

1-954 

•0413 

112 

1-163 

•0694 

550 

2-056 

•0385 

122 

1-184 

•0682 

600 

2-150 

•0376 

132 

•204 

•0671 

650 

2-260 

•0357 

142 

•224 

•0660 

700 

2-362 

•0338 

152 

•245 

•0649 

750 

2-465 

•0328 

162 

•265 

•0638 

800 

2-566 

•0315 

172 

•285 

•0628 

850 

2-668 

•0303 

182 

•306 

•0618 

900 

2-770 

•0292 

192 

1-326 

•0609 

950 

2-871 

•0281 

202 

1-347 

•0600 

1000 

2-974 

•0268 

294         LIQUID  FUEL  AND  ITS   APPARATUS 


TABLE  XXV.  Table  showing  Number  of  British  Thermal  Units  con- 
tained in  one  pound  of  pure  Water  at  varying  temperatures  and 
densities,  and  pounds  per  gallon. 


Density 

Number 

Density 

Number 

Tem- 
pera- 
ture. 

or 

Weight 
of 

of 
Thermal 
Units 

Pounds 
Weight 

Tem- 
pera- 
ture. 

or 

Weight 
of 

of 
Thermal 
Units 

Pounds 

Weight 

Deg. 
Fahr. 

1  Cubic 
Foot. 

in  1 

pound  of 

per 
Gallon. 

Deg. 
Fahr. 

1  Cubic 
Foot. 

in  1 
pound  of 

per 
Gallon. 

Pounds. 

Water. 

Pounds. 

Water. 

1 

2 

3 

4 

1 

2 

3 

4 

*32 

62-418 

32-000 

10-0101 

135 

61-472 

135-217 

9-859 

35 

62-4212 

35-000 

10-0102 

140 

61-381 

140-245 

9-844 

t39-l 

62-425 

39-001 

10-0112 

145 

61-291 

145-275 

9-829 

40 

62-425 

40-001 

10-0112 

150 

61-201 

150-305 

9-815 

45 

62-422 

45-002 

10-0103 

155 

61-096 

155-339 

9-799 

50 

62-409 

50-003 

10-0087 

160 

60-991 

160-374 

9-781 

55 

62-394 

55-006 

10-0063 

165 

60-843 

165-413 

9-757 

60 

62-372 

60-009 

10-0053 

170 

60-783 

170-453 

9-748 

65 

62-344 

65-014 

9-9982 

175 

60-665 

175-497 

9-728 

70 

62-313 

70-020 

9-9933 

180 

60-548 

180-542 

9-711 

75 

62-275 

75-027 

9-9871 

185 

60-430 

185-591 

9-691 

80 

62-232 

80-036 

9-980 

190 

60-314 

190-643 

9-672 

85 

62-182 

85-045 

9-972 

195 

60-198 

195-697 

9-654 

90 

62-133 

90-055 

9-964 

200 

60-081 

200-753 

9-635 

95 

62-074 

95-067 

9-955 

205 

59-93 

205-813 

9-611 

100 

62-022 

100-080 

9-947 

210 

59-82 

210-874 

9-594 

105 

61-960 

105-095 

9-937 

J212 

59-76 

212-882 

9-565 

110 

61-868 

110-110 

9-922 

230 

59-36 

231-153 

9-520 

115 

61-807 

115-129 

9-913 

250 

58-75 

251-487 

9-422 

120 

61-715 

120-149 

9-897    • 

270 

58-18 

271-878 

— 

125 

61-654 

125-169 

9-887 

290 

57-59 

292-329 

— 

130 

61-563 

130-192 

9-873 

*  32°F.     =  Freezing  point  of  water. 

f  39'1°F.  =  The  temperature  at  which  water  is  at  its  greatest  density. 
%  212°F.  =  Boiling  point  of  water. 

A  British  Thermal  Unit  (B.Th.U.)  =  that  quantity  of  heat  that  is    required   to 
raise  one  pound  of  water  through  one  degree  Fahr.  at  or  near  39'1°F. 


TABLE  XXVI.     Saturated  Steam. 


Saturated  Steam  is  dry  steam  at  the  maximum  pressure  and  density, 
due  to  its  temperature — not  superheated.  It  is  attained  when  all 
latent  heat  required  for  the  steam  has  been  taken  up — this  is  called 
"  Saturation  Point."  A  vapour  not  near  the  saturation  point  behaves 
like  a  gas  under  changes  of  temperature  and  pressure  ;  if  it  is  compressed 


TABLES 


295 


or  cooled  it  reaches  a  point  where  it  begins  to  condense ;   it  then  no 
longer  obeys  the  same  laws  as  a  gas. 

Heat  and  Work  required  to  generate  1  Ib.  of  Saturated  Steam  at  212°F.  from 

Water  at  32°F. 


Distribution  of  Heat. 

Units  of  Heat. 

Mechanical 
Equivalent  in 
foot  pounds. 

THE  SENSIBLE  HEAT  — 
1.  To  raise  the  temperature    of   the 
water  from  32°-212°  .... 
THE  LATENT  HEAT  — 
2.  In  the  formation  of  steam 
3.  In   expansion   against   the   atmo- 
spheric pressure                 .      .      .  ~ 

180-9 
894-0 
71-7 

140,740 
695,532 
55  783 

TOTAL  OF  \VORK                   

1,146-6 

892  055 

TABLE  XXVII.     Factors  of  Evaporation. 


Gauge  Pressure  of  Steam  in  pounds  per  Square  Inch. 


0 

20 

40 

60 

80 

100 

Temp,  of 
Feed 
Water. 

120 

150 

180 

200 

•187 

1-201 

1-211 

1-217 

1-222 

1-227 

32 

•231 

•236 

•240 

1-243 

•179 

1-193 

1-203 

1-209 

1-214 

1-219 

40 

•222 

•227 

•232 

1-234 

•168 

1-182 

1-192 

1-198 

1-203 

1-208 

50 

•212 

•217 

•221 

1-224 

•158 

1-172 

1-182 

1-188 

1-193 

1-198 

60 

•202 

•207 

•211 

1-214 

•148 

1-162 

1-172 

1-178 

1-183 

1-188 

70 

•191 

•196 

•200 

1-203 

•137 

1-151 

1-161 

1-167 

1-172 

1-177 

80 

•181 

•186 

•190 

1-193 

•127 

1-141 

1-151 

1-157 

1-162 

1-167 

90 

•170 

•176 

•180 

1-183 

1-117 

1-131 

1-141 

1-147 

•152 

1-157 

100 

•160 

•165 

•170 

1-172 

1-106  il-120 

1-130 

1-136 

•141 

•146 

110 

•150 

•155 

•159 

1-162 

1-096 

1-110 

1-120 

1-126 

•131 

•136 

120 

•140 

1-145 

•149 

•151 

1-085 

1-099 

1-109 

1-115 

•120 

•125 

130 

•129 

1-134 

•138 

•141 

1-075 

1-089 

1-099 

1-105 

•110 

•115 

140 

•119 

1-124 

•128 

•131 

1-065 

1-079 

1-089 

1-095 

•100 

•105 

150 

•109 

1-113 

•117 

•120 

1-054 

1-068 

1-078 

1-084 

•089 

•094 

160 

•098 

1-103 

•107 

•110 

1-044 

1-058 

1-068 

1-074 

•079 

•084 

170 

•088 

•092 

•096 

•099 

1-033 

1-047 

1-057 

1-063 

•068 

•073 

180 

1-077 

•082 

1-086 

•089 

L-023 

1-037 

1-047 

1-053 

1-058 

•063 

190 

1-066 

•071 

1-076 

•078 

1-013 

1-027 

1-037 

1-043 

1-048 

•053 

200 

1-056 

•061 

1-065 

•068 

1-004 

1-017 

1-027 

1-033 

1-038 

•043 

210 

1-046 

•051 

1-055 

1-057 

1-002 

1-000 

212 

Formula  from  which  the  above  figures  are  calculated  — 
H=TS-TW. 


TS  =  Total  amount  of  heat  contained  in  one  pound  of  steam  at 
absolute  steam  pressure  —  column  4,  Table  XXVI. 

TW  =  Total  heat  of  water  at  feed  water  temperature  —  column  3 
Table  XXV. 

H  =Heat  imparted  to  water  (TW  to  convert  into  steam  TS), 

LS=Latent  heat  of  steam  at  atmospheric  pressure  965-7. 

F=  Factor  of  evaporation. 


296         LIQUID  FUEL  AND  ITS  APPARATUS 

Saving  effected  ~by  heating  feed  water. 

The  saving  in  fuel  effected  by  heating  feed  water  can  be  calculated 
by  formula  as  below — 

100  (T— t) 
Percentage  of  saving  =  — TT_+ — 

in  which  T=  heat  units  in  one  pound  of  feed  water  above  0°  after 

heating — column  3,  Table  XXV. 
t  =heat  units  in  one  pound  of  feed  water  above  0°  before 

heating— column  3,  Table  XXV. 

H=heat  units  in  one  pound  of  steam  of  boiler  pressure  above 
0°— column  4,  Table  XXVI. 


TABLE  XXVIII. 


Heat  Balance  or  Distribution  of  the  Heating  Value  of 
the  Combustible. 


TOTAL  HEATING  VALUE  OF  1  LB.  OF  COMBUSTIBLE  B.Tn.U. 


B.Th.U.  =. 
per  cent. 


1.  Heat  absorbed  by  the  boiler  =  evaporation  from  and  at 

212  degrees  per  Ib.   of  combustible  x  965-7. 

2.  Loss  due   to   moisture  in   coal=per   cent,    of  moisture 

referred  to  combustible  +  100  x  [(212  -  1)  x  966  X  0-48 
(T-212)].  (t  =  temperature  of  air  in  the  boiler 
room,  T=that  of  the  flue  gases). 

3.  Loss  due  to  moisture  formed  by  the  burning  of  hydrogen 

=per  cent,  of  hydrogen  to  combustible  -^by  100  x  9 
X[(212-tx  966x0-48)  (T-212)]. 

*4.  Loss  due  to  heat  carried  away  in  the  dry  chimney  gases 
=weight  of  gas  per  Ib.  of  combustible  X  0-24  x  (T—  t). 
f5.  Loss  due  to  incomplete  combustion  of  carbon 
CO        ,xper  cent.  C  in  combustible 

-"  -x  10-150 


6.  Loss  due  to  unconsumed  hydrogen  and  hydrocarbons, 
to  heating  the  moisture  in  the  air,  to  radiation,  and 
unaccounted  for. 

(Some  of  these  losses  may  be  separately  itemized 
if  data  are  obtained  from  which  they  may  be  cal- 
culated. ) 


TOTALS 


100-00 


*  The  weight  of  gas  por  Ib.    of   carbon   burned  may  be    calculated  from   the  gaa 
analysis  as  follows — 

Dry  gas  per  Ib.  carbon  -11  CQ2  +  8  O  +  7  (CO  N) 

3  (C02  +  CO) 

in  which  CO2,  CO,  O,  and  N  are  the  percentages  by  volume  of   the   several  gases. 
The  weight  of  dry  gas  per  Ib.  of  combustible  is  found  by  multiplying  the  dry  gas  per 
Ib.  of  carbon  by  the  percentage  of  carbon  in  the  combustible  and  dividing  by  100. 
Professor  Jacobus  recommends  the  use  of  the  following  formula  for  finding   the 
weight  of  air  per  Ib.  of  carbon — 

C  7  N  . 

3  (C02  +  CO)    ' 

t  CO2  and  CO  are  respectively  the  percentage  by  volume  of  carbonic  acid  and  car- 
bonic oxide  in  the  flue  gases.  The  quantity  10  150  =number  of  heat  units  generated 
by  burning  to  carbonic  acid  one  Ib.  of  carbon  contained  in  carbonic  oxide. 


TABLES 


297 


TABLE  XXIX. 

Showing  Heat  Loss  in  Chimney  Gases  according  to  Percentage  of 
Carbon  Dioxide  and  Temperature  Efficiency. 


fyO                       50                         60                          70                         80 

8             9           10         12      1Z     13   11,.  151617 

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10 

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mz 

1076 
10t>0 
WOtf. 
968 
93Z 
896 
860 
821, 
783 
752 
716 
680 
6k& 
612 
572 
536 
500 
1+61* 
t<Z6 
392 
356 
3ZO 
£54 

zt*a 

Z12 
176 
ll+O 
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INDEX 


A 

Abergele  accident,   184 
Acetylene,  289,  82 
Adiabatic  compression,  242 
Admiralty  flash  tests,   130 
Ados,  Co2  recorder,  236 
Advantages  of  Liquid  Fuel,  55 
Aerated  fuel  system,  267 
Air,  atomizing  by,  133,  222 

—  calculation  of,  247 

—  compression,  242 

-  efflux,  238,  248 

-  for  atomizing,   133,    214,   222, 

247 

—  for  combustion,  37,  40,  288,  290 

—  for  combustion,  Rankine,  114 

—  for  combustion,  Longridge,  1 14 

—  heater,   166 

—  heater,  Ellis  &  Eaves,  223 

—  heating,  166 

—  lift  pump,  33 

—  low  pressure,  212,  269 

—  power  to  compress,  242 

—  pressure  diagram,  242 

—  properties  of,  82 

—  regulator,  202 

—  tuyere,  202 
Alcohol,  282 
Allest  atomizer,  261 

Allo tropic  forms  of  carbon,  78,  1 15 
Alsace  oil,  46,  281 
American  gallon,  44 
American  locomotive  practice,  162, 
178 

—  petroleum,  44 

-  petroleum  production,  26 

—  stationary  practice,   195 
Amorphous  carbon,  78 
Analysis  of  Borneo  oil,  208,    212 

-  chimney  gas,  233 

-  coal,   112 

-  firebrick,  70,  71 

-  fireclay,  70,  71 


299 


Analysis  of  flame,   118 

-  flue  gases,  233 

—  oil,  48 

—  petroleum,  48 

—  Texas  oil,  48 
Anthracite,   139,  116,  111 
Anticline,  30 
Apparatus,  Orsat's,  236 
Arch,  firebrick,  67 
Area  of    chimney,  239 
Arlberg  tunnel,   171 
Arndt  econometer,  236 
Astatki,  36,  65,  208 
Atmosphere,  82 
Atomizers,  various,  37,  250 
Atomizer  Aerated  Fuel  Co.,    250 

—  Baldwin,   179,  250 

—  Bereznef,  37 

—  Billow,   196,  207,  250 

-  Circular,   36,  262 

—  d' Allest,  261 

—  elementary,  256 

—  flat  jet  type,  264 

—  Fvardofski,  262 

—  Gregory,  265 

—  Guyot,  250 

—  Holden,   157,  250 

—  Hoveler,  267 

—  hydroleum,  250 

—  Kermode's,  250 

—  Korting,   153,  250 

—  nozzles,  259 

—  Orde,  144 

—  power  of,  259 

—  proportions,  261 

—  Rusden-Eeles,  134,  250 

—  Soliani,  263 

—  Southern  Pacific  Railway,  264 

—  Swensson,  250 

—  types  of,  250 

—  Urquhart,   193,  250 

—  Wallsend,   148 

—  Williams,  56 
Atomizing,  42,  214 


300 


INDEX 


Atomizing,  M.  Bertin  on,  153,  259 

—  agent,  214 

—  necessity  of,  42 

—  with  air,  133,  214,  222,  247 

—  with  steam,  133,  214,  222 
Aude,  T,  259 


Baku  petroleum,  53 
Baldwin  atomizer,   179 

-  firebox,  180 

—  oil  fuel  system,   179 
Ballast  tanks,  129 
Barometer,  83 
Barrels  of  oil  produced,  26 

—  and  gallons,  49 
Beaumont  oil,  39,  50 

—  tests,  56 
Bereznef  atomizer,  36 
Berthelot  on  carbon,    79 
Berthelot-Mahler  calorimeter,  91 
Berthelot  on  latent  heat  of  carbon, 

79 
Bertin  on  air  compressing,  246 

—  on  atomizing,  153 

—  on  liquid  fuel,  37 

—  on  mixed  system,  37,   172 

—  on  ratio  of  oil  and  coal,  38 
Billow  atomizer,  207 

-  system,  195 

Bituminous  fuel   combustion,  40, 

116,  112 
Blast  furnace  gas,  283 

—  oil,  41,  47 

Blast  pipe,   variable,  Macallan's, 

170,  240 

Blocks,  fireclay,  41 
Boiler,  Belleville,  110 

—  choice  of,  24,  25 

—  water,  capacity  of,   132 

—  Cherbourg,  264,   176 

—  Du  Temple  type,   146 

—  firefloat  burner,  219 

—  French  torpedo  boat,  38 

—  Godard,  258 

—  Guyot,   176 

—  hydroleum  special,  215 

-  Lancashire,   145,   167,   168 

—  Lancashire,  Orde's  system,  145 

—  locomotive,   154 

—  marine,   133 

-  marine  type,   173 

—  Solignac,  25 

—  underfired  tubular,  205 

—  water  capacity  of,  24 


Boiler,  water  tube,   169,  206 

—  without  grate,   169,  206,  213 

—  Weir,  40,   121 

Boiling  point  of  petroleum,  64 

Boring  oil,   31 

Borneo  oil,  212,  63,  208 

Brick,  see  Firebrick 

Brick  arch,  67 

—  linings,  67 
Bridge  walls,  40 

British  Thermal  Unit,  294 

Buffle,  259 

Bulkheads,   128 

Bunker  pipes  of  oil  supply  system, 

137 
Bunker  pump,  Weir's,  231 

—  fuel  oil,  231 
Burma  oil,  281,   63 
Burner,  Clarkson-Capel,  218 
Burners,  see  Atomizers,  250 

-  Symon  House,  257 
Burning  of  firebrick,  69 
Butane,  62 

C 

Calculation  of  temperatures,   100 
Californian  petroleum,  44,   45 
Calorific  formula,  90 
Calorific  power  of  Borneo  oil,  63 

—  Burma  oil,  63 

—  carbon,  78 

—  Caucasus  oil,  63 

—  gases,  283 

—  hydrogen,  81 

—  liquid  fuel,  53,  99,  281,  284 

—  Clavenad  on,   107 

—  Texas  oil,  53,  63 
Calorimetry,  91,   236 
Calorie,  90 

Calorimeter,  Berthelot-Mahler, 2 37 

Canada  oil,  281 

Capacity  of  boilers,  water,  132 

Cap  damper,  chimney,  240 

Carbolic  acid,  47 

Carbon,  allo tropic  forms,  78,  115 

—  amorphous,  78 

—  as  fuel,  78 

-  atomic  weight,  78 

-  bisulphide,  79 

—  calorific  power  of,   78 

—  combustion  of,  79 

—  diamond,  78 

—  dioxide,  79 

—  gaseous,  79 


INDEX 


301 


Carbon,  graphitic,    78 

—  heat  of  combustion,  78,  285 

—  heat  of  conversion,  78,  79 

—  in  nature,  78 

—  "liquid,"  45,    79 

—  monoxide,  78 

—  properties  of,  78,  285 

—  solid,  78 

—  vapour,  79 
Carbonic  acid,  78 

—  oxide,  78 
Carborundum,  67 

Cargo  steamer,  ordinary  with  oil 

fuel,   127 

Car  hose,  tank,  201 
Carriage  of  oil,  35,  228,   139 
Casing,   33 
Cast  iron,  66 
Cement  for  oil  pipes,   128 
Centigrade  thermometer,  93 
Chamber,  combustion,  73,   123 
Charcoal,  see  Amorphous  carbon 
Chemical  properties  of  air,  82 

—  carbon,  78 

—  hydrogen,  81 

—  nitrogen,  84 

—  oil,  62 

—  oxygen,  83 

—  petroleum,  62 

—  Texas  oil,  45 
Chemistry,  Thermo-,  90 
Cherbourg,  test  at,   175 

—  boiler,  176,  264 
Chicago  Exhibition,  21 
Chimney  area,  239 

—  damper  cap,  240 

—  draught,  237 

—  gases,  297 

Circular  atomizers,  36,  262 
Classificationof  fireclay  goods,  76 
Clarkson-Capel  burner,  218 
— -  preliminary  heater,  219 

—  system,  218 

Clavenad  on  calorific  capacity  of 

fuel,  107 

Clay,  see  Fireclay 
CO2  analysis,  233 

—  in  furnace  gases,  233 

—  recorder,  Ados,  236 

—  recorder,  Arndt,  236 

—  Simmance  Abady,  236 
Coal,  analysis  of,  112 

—  anthracite,   116,  139 

—  combustion  of,  108 

—  long-flaming,   117 


Coal,  short-flaming,   117 

—  Welsh,  117 

—  and  oil  furnace,  134 

—  and  oil,  comparative  cost,  132, 

183,  286 

—  production,  22 

—  tar,  41 

Coefficient  of  expansion,  oil,  129, 
281 

—  water,  85 

—  gases,  282 
Cofferdams,   128 

Coils,  heating,   140,   155 
Combustion,  air  for,  37,  288,  290 

—  oxygen  for,  288,  290 

—  of  anthracite,   116,   139 

—  of  bituminous  fuel,  40,  112,  116 

—  calculations,  78,   100 

—  smokeless,   108 

—  of  carbon,  79 

—  of  hydrogen,  81 

—  chamber,  refractory,   123 

—  chamber,  73 

—  imperfect,   108 

—  heat  of,  63,  109,  288 

—  of  liquid  fuel,  63 

—  of  hydrocarbon,   109 

—  of  vaporized  liquids,  218,  257 

—  principles  of,  39 

—  temperature  of,   100 

—  volume  of  gases,   103 
Comparative  costs,  oil  and  coal, 

36,  59 

Compounds,  hydrocarbon,  62,  112 
Compression,  adiabatic,  242 

—  of  air,  242 

—  compound,  242 

—  diagrams,  242 

—  isothermal,  242 
Conversion,  metamorphic,  of  car- 
bon, 78,   115 

Construction  of  furnace,  203 
Controlling  valves,   160 
Corsicana  petroleum,  51 
Cost,  comparison  of  coal  and  oil, 
35,   183 

—  of  oil,  36 
"Cracking,"  52 
Cranes,  oil,  230 
Creosote,  41,  46 
Cresylic  acid,  47 

Crude  oil,  41,  44,  281,  284 
Curves  of  compression  of  air,  244 
Curves    of    performance,    Grazi- 
Tsaritzin  Railway,   194 


302 


INDEX 


d'Allest's  atomizer,  261 
Damper,  chimney  cap,  240 
Danger  of  oil,  36 
Density  of  petroleum,  49,  65,  183 
Denton,  Prof.,  on  Texas  oil,  59 

—  evaporative  duty,  59 

—  cost  of  oil,  59 
Deterioration  by  storage,  65 
Diamond,  78 

Diesel  engine,  270 
Dinas  firebrick,  67 
Dissociation  of  steam,  etc.,  87,  97 

-  gases,  97,  102 
Dioxide  of  carbon,  78 
Distillation,  fractional,  48 
Distribution  of  liquid  fuel,  228 
Dowlais  firebrick,  67 
Draught,  237 
Draught  gauge,  239 
Dudley's  formula  for  relative  cost 

of  oil  and  coal,  183 
Dutch  Navy,  130 
Dulong's  formula,  91 

E 

Earnshaw  on  Texas  oil,  51 
Econometer,  Arndt,  236 
Economics  of  liquid  fuel,  35 
Efficiency  of  evaporation,  58 

—  Texas  oil,  56 
Efflux  of  air,  238,  248 
Elementary  atomizer,  256 
Ellis  &  Eave's  air  heater,  223 

—  system,  222 
Endothermism,  90,  92 

English  locomotive  practice,   154 

—  stationary  practice,  208 
Ethane,  62,  82,  202,  282,  289 
Equivalent,  Joule's,  285 

—  mechanical,  of  heat,  285 
Evaporation,  factors  of,  295 

—  per  unit  of  various  fuels,    104 
Evaporative  duty,  59,   104,  291 

—  efficiency,  58 
Everhart  on  Texas  oil,  48 
Exothermism,  38,  92 
Expansion  of  oil,  129,  281 

—  water,  85 
Explosions,  229 


Factors  of  evaporation,  295 
Factor,  load,  24 


Fahrenheit  thermometer,  93 
Feed,  oil,   161 

Firebox,     American     locomotive, 
163,   171 

—  Baldwin,   180 

—  Cherbourg  boiler,   176,  264 

—  Holden,  165 

—  Lancashire,   167 

—  locomotive,  168 

—  Southern  Pacific,   171 

—  Urquhart,   188 
Firebricks,  67 

— aluminous,  76 
Firebrick,  analysis,  70,  71 

—  arch,  67 

—  burning,  69 

—  classification,  76 

—  carborundum,  67 

—  carboniferous,  96 

—  Dinas,  67 

—  Dowlais,  67 

—  French,  67,  70 

—  general  particulars,  67 

—  Glenboig,  67 

—  manufacture,  67 

—  Newcastle,  67 

—  Pearson,  68 

—  silica,  70 

—  Stourbridge,  67 
Fireclay,  analysis,  70,  71 

—  blocks,  41 

—  Dinas,  67 

—  Dowlais,  67 

—  Gartcosh,  73 

—  Glenboig,  67 

—  Kilmarnock,  71 

—  Newcastle,  67 

—  Stourbridge,  67 
Flame,   117 

—  testing,  118 

—  length,  38,   117 
Flannery-Boyd  system  of  oil  fuel, 

129,   136 

—  oil  storage,   127 
Flash  point,  39,  65,   130 
Flue  gas  analysis,  233 
Forbin,  test  of,   177 
Forced  draught,  240 
Fractional  distillation,  48 
French  firebrick,  67 
French  Navy  tests,  175 

Fuel,  evaporative,  power   of,  69, 
104,  291 

—  gas,  283 

—  oil,  212 


INDEX 


303 


Fuel,  oil  bunker,  142 

—  oil  distribution,  228 

—  oil  production,  26 

—  pumping,  231 

—  pump,  Weir's,  231 

—  oil  tanks,  229 
Furieux,  tests  with,   175 
Furnace,  Ellis  &  Eaves',  222 

-  brickwork  walls,  etc.,   146 

-  construction,  203 

-  Lancashire,   145,   165 

-  firebricks,  67 

—  lining,  39,   111,  146 

—  locomotive,   168 

—  management,   187 

—  marine,   133,   173 

—  oil  and  coal,  211 

—  oil,  209 

-  temperatures,   112,  81,  293 

—  water  tube,  213 
Fvardofski  atomizer,  262 

—  system,  262 


G 


Gallon,  American,  44,    183 

—  English,   182 
Gallons,  per  barrel,   183 
Galician  oil,  53 
Ganister,  67 
Gartcosh  fireclay,  73 
Gas,  analysis,  233 

—  blast  furnace,  283 

—  density,  285,  290 

—  dissociation  of,  97 

—  expansion  of,  282 

—  fuel,  283 

—  hydrogen,  283 

—  marsh,  283 

—  sp.  heat,  283,   284 

—  tar,  43,  47,  214 

Gases,  calorific  capacity  of,  283 

—  of  combustion,  volume  of,  103 

—  chimney,  297 
Gaseous  carbon,  79 
Gauge,  draught,  239 
Gear,  marine  furnace,   133 
General  arrangement,   137 

—  Korting  system,   152 
General  considerations,  21 
Geology,  28 

German  oil,  281 
Glass,  violet,   121 
Glenboig  clay,  67 
Godard  boiler  test,  258 


Graphite,  78 

Grate,  boilers  with,  211 

—  boilers  without,  210,  215,  206 
Gravity,  99 

-  specific,  286,  287 
Grazi-Tsaritzin  Railway,   184 

—  curves  of  performance,   194 

—  fuel  tank,  231 

—  locomotive,  189 

—  oil  distribution,  228 

—  tender,   190 

Great  Eastern  Railway,  154 

—  locomotives,   165 

—  storage  system,  223 

—  tender,   165 
Griffin  Engine,  270 
Guyot  atomizer,  254 

—  boiler,   176 


Hanover  oil,  50,  53 
Hard  water,  88 
Howden's  system,  133,   143 
Heat,  92 

—  of  combustion  of  carbon,  80,  99 

—  of   combustion   of  petroleum, 

etc.,   108,   109 

—  latent,  of  carbon,  90 

—  of  dissociation,  79 

—  latent,  96 

—  mechanical  equivalents  of,  98 

—  of  metaphoric  conversions,  78 

—  quantity  of,  92,  97 

—  specific,  94 

—  thermometric,  92 

—  units,  90 

Heater,  Clarkson-Capel  prelimin- 
ary, 218 

—  Ellis  &  Eaves  air,  223 
Heating  air,  166,  223 

—  coils,  223 

—  oil,  263 

Holden  atomizer,  157 

—  system,  154 
Hornsby  Engine,  282 
Hose,  201 

Hose,  tank  car,  201 
Hoveler  system,  267 
Howden's  system,   133,  143 
Hydrocarbon  compounds,  62,112 

—  combustion  of,   109 
Hydrogen,  calorific  power  of,  81 

—  combustion  of,  81 

—  gas,  81 


304 


INDEX 


Hydrogen  properties  of,  81 

-  temperature  of  ignition,  82,  119 
Hydroleum  special  boiler,  215 

—  atomizer,  250 

—  system,  214 


Ignition  temperature,  82,  119,  292 

Imperfect  combustion,  102 

Indret,  tests  at,   176 

Injector,  see  Atomizer 

Interchange  of  coal  and  oil,  134 

Iron,  cast,  66 

Isothermal  compression,  242 


Japanese  railways,  162 
Jeanne  d'Arc,  the,  174 
Joule,  Dr.,  98 

K 

Keller,  tests  by,  37 
Kelvin  law,  26 
Kermode's  atomizer,  250 

—  system,  208 
Khodoung,  s.s.,  143 
Kilmarnock  fireclay,  71 
Kilns,  oil  fired,  74 
Kimeridge  clay,  28 
Korting  atomizer,   153 

—  system,   152 
Koudako  oil,  49 


Laeisz,  F.  C.,  s.s.,   143 
Lamp  oil,  43,  218 
Lancashire  boiler,   145,   167 
Latent  heat,  96,   113 
Latitude  and  barometer,  83 
Length  of  flame,  38,   117 
Lighting  up,  187 
Lima  oil,  184 

Lining  furnace,  39,  111,  146 
"Liquid"  carbon,  45 

—  combustion,  38 
Liquid  fuel,  37 

—  advantages  of,  55 

—  at  sea,  127 

—  containing  oxygen,  47 

—  distribution,  228 

—  economics  of,  35 

—  price  of,  35,  59 


Liquid  fuel,  production,  26 

-  properties  of,  49,  65,   183 

—  system,      Wallsend      Slipway 

Co.,  143,   146 

—  varieties  of,  43 
Load  factor,  24 
Locomotive,  American,   162,   178 

—  boiler,   154,   178 

-  Cherbourg,  264 

-  firebox,   154,   163,   171 

—  Fvardofski,  262 

-  Great  Eastern  Railway,   154 

-  practice,  American,   162,   178 

—  practice,  English,   154 

—  practice,  Russian,   178 

—  Southern  Pacific,  171 

—  Vladi  Kavkaz  Railway,   153 

-  Urquhart,   184 

Low  pressure  air,  212,  269 
Loss  by  excess  of  air,  297 

M 

Mabery  on  Texas  oil,  50 
Macallan  variable  blast  pipe,  170. 

240 

Management  of  furnace,   187,  204 
Manufacture  of  firebrick,  67 
Marine  boiler,  173 

—  type  boiler,     173 

—  furnace  gear,   133,   173 
Marsh  gas,  see  Methane 
Materials,  66 

Mazout  or  Mazut,  see  Astatki 
Mechanical  stoking,  24 

—  equivalent  of  heat,  98 
Metallurgy,  application  of  liquid 

fuel  to,  267 

Metal  and  refining  furnace,  266 

Metamorphic  conversion  of  car- 
bon, 78,  115 

Methane,  22,  82 

Meyer  system,  172 

Milan,  test  on,   177 

Mixed  system  of  coal  and  oil 
combustion,  35,  172 

Moat,  round  oil  stores,  228 

Monoxide  of  carbon,  78 

Murex,  s.s.,   127,  133 

N 

Nacogdoches  oil,  48 
Naphthalene,  47 

National  Fuel  Oil  Co.'s  system, 
95 


INDEX 


305 


Navy,  British,  21,  130 

—  Dutch,   130 

—  French,   175 

—  German,   130 

—  Italian,   258 

—  Russian,  65 
Newcastle  fireclay,  67 

—  coal,  47,   112 

New  York,  s.s.,  liquid  fuel  for,  138 
Nitrogen,  84 

—  in  atmosphere,  84 

—  properties  of,  84 
Nozzles  of  atomizers,  259 


Oil,  Alsace,  53,  46 

—  American,  44,  46 

—  Baku,  53,  284,   36 

—  Beaumont,  39 

—  blast  furnace,  47 

—  boring,  31 

—  Borneo,  63,  212,  208 

—  Burma,  281,  63 

—  California,  44,  54 

—  Canada,  281,  46 

—  Corsicana,  51 

—  creosote,  46 

—  crude,   183,  281,  284,  46 

—  drilling,  32 

—  fuel,  212,  284 

-  Galicia,  53,  46 

-  Gold  Coast,  49 

-  Hanover,  50,  53 

-  Koudako,  49 

—  lamp,  218,  43 

-  Lima,   184 

-  Nacogdoches,  48,  51 

—  Pennsylvania,  46,  49,  53,  286 

-  reduced,  44 

-  residuum,   36,  42,  287 

-  Roumanian,  46,  49 

-  Russian,  46,  286 

-  shale,  47 

-  Sour  Lake,  51 

—  Texas,  45,  49 

—  Wyoming,  86 

—  Zante,  49 

—  and  coal,  comparative  cost,  38, 

286 

-  and  coal  furnace,    136 

—  burner,  see  Atomizers 

—  calorific  power,  281,  284 

—  carriage  of,   35,   139,  228 

-  cranes,  231 


Oil  engines,  271 

—  expansion,   129,  281 

—  explosions,  229 

—  distribution,  228 

—  feed,  161 
Oil  furnaces, 

—  furnace,  Baldwin,   178 

—  engines,  271 

-  Cornish,  see  Lancashire 

—  Holden,   165,   168 

—  Lancashire,   168 

—  locomotive,   154-178 

-  water  tube  boiler,   169 
Oil  heating,  263 

—  pressure,  269 

—  pipes,  229 

—  pump,  231 

—  pumping  system,   196,  32 

—  ratio  to  coal,  54 

—  regulation,   161,  179 

—  regulator,   161,   179 

—  safety  moat,  228 

—  service  pumps,   196,  231 

—  steamers,  recent,   1'29 

—  storage,   127,   228 

—  stratification,  30 

—  tank  steamer,   138 
Orde  atomizer,   144 

—  boiler,  Lancashire,   145 

—  on  liquid  fuel,  63 

—  system,  140,  143 

—  water-tube  boiler,  141 
Orsat-Lunge  apparatus,  236 
Oxygen,  83 


Packman,  s.s..  133 

Pakin,  test  on,   177 

Paraffin,  221 

Paul,  Dr.,  on  liquid  fuel,  62 

Pearson  firebricks,  68 

Pelouze  and  Cahours  on  hydrocar- 
bons, 64 

Pennsylvania  oil,  49,  286 

Performance  curves,  Grazi-Tsarit- 
zin  Railway,  194 

Petroleum 

—  American,  44 

-  analysis  of,  48 

-  Baku,  53,  284 

-  Borneo,  212,  63 

-  Burma,  281,  63 

—  boiling  point,  64 

—  California,  44,  54 

-  combustion  of,  109,  218,  257 


306 


INDEX 


Petroleum,  Corsicana,  51 
— -  drilling,  32 

—  fuel,   183 

—  geology,  28 

—  production  of,  26 

—  properties  of,  49,  65,  183 

—  pumping,   32 

—  residuum,  36,  42,  287,  291 

—  Russian,  46,  286 

—  storage  precautions,  228 
-  Texas,  45,  49 

Phillips  on  Texas  oil,  49 
Physical  properties  of  oil,  49,  65, 

183 
Pipes,  88,  229 

—  bunker,   128,   137 

—  jointing,  128 

—  jointing  cement,   128 

—  water,  88 

Pood,  its  equivalent,  230 
Power  to  compress  air,  247 
Precautions  in  oil  storage,  228 
Preliminary  heating,  218 
Pressure  systems,   196 
Price  of  oil,  35,  59 

—  per  barrel,  36,  54,  59 

—  per  gallon,  36,  44 
Principles  of  liquid  fuel  combus- 
tion, 38 

Production  of  coal,  22 
Propane,  62,  82 
Properties  of  air,  82 

—  American  oil,  44,  46- 

—  Borneo  oil,  63,  208,  212 

—  carbon,  78,  285 

—  firebricks,  67 

—  fireclay  67 

—  gases,  283 

—  hydrogen,  81 

—  liquid  fuel,  49,  65,   183 

—  nitrogen,  84 

—  oxygen,  83 

—  petroleum,  49 

—  Russian  oil,  46,  256 

—  Texas  oil,  45,  51 

—  water,  84 

Proportions  of  atomizers,  261 
Propylene,  82 
Pulverizers,  see  Atomizers 
Pump,  Weir's  bunker,  232 

—  Weir's  oil,  232 
Pumping  systems,   196 
Pumps,  oil,  231 
Pyrometers,  94 


Q 

Quantity  of  heat,  92,  97 

R 

Ragosino  effect  of  steam  on  oil,  260 
Ratio,  oil  to  coal,  38 
Reaumur's  thermometer,  93 
Reduced  oils,  44 
Refractory  combustion  chamber. 
73 

—  linings,  39,  73,   111,   146 
Regulating  gear,  161,  179 
Regulation  of  oil,  161,   179 
Regulator,  air,  202 

—  oil,  Baldwin  179 

—  oil,  G.E.  Rly.,  161 
Relative  cost,  oil  and  coal,    132, 

183,  268,  286,   191 
Residuum,  36,  42,   197 
Ringelmann's  smoke  chart,  123 
Riveting,  128 
Roumanian  oil,  49 
Rules  for  liquid  fuel  ships,  127 
Rusden-Eeles  atomizer,   134 
Russian  locomotives,   191 

—  Navy,  65 

—  oil,  46 

Ruston  Proctor  Engine,  271 

S 

Safety  moat  round  tanks,  228 
St.  Glair  Deville,   102 
Salts,  solubility  of,  87 
Sea  water,  88 

Serpollet  on  vaporizing,  263 
Service,  oil  pumps,  231,  196 
.Shale  oil,  47 

—  tar,  47 
Silica,  67-77 
Siloxicon  77 

Simmance  Abady   CO2  recorder, 

236 

Siihonia,  s.s.,  143 
Small  tube  boiler,   1  H 
Smoke,  82,   109 

—  chart,  Ringelmann's,   123 

—  prevention,   109 
Soft  water,  88 
Soliani  atomizer,  263 
Solignac  boiler,  25 
Solubility  in  water   of  salts,  87 
Soot,  82 

Sour  Lake  oil,  51 
Southern  Pacific  Railway,  36,  54, 
171,  264 


INDEX 


307 


Specific  gravity,  46,    49,   65,   164 
Specific  heat,  94 

—  gases,  95 

—  ice,   86 

—  solids,  284 

—  water,  86 
Sprayer,  see  Atomizer 
Springfield  system,  269 
Stationary     practice,     American, 

195 

—  English,  208 
Steam,  as  fuel,   15 

—  atomizing,   133 

-  dissociation  by  heat,  87,  97 

—  per  pound  of  oil,  258 

—  ships,  F.  C.  Lacisz,   143 

—  Murex,  127,   133 

—  Neivyork,   139 

—  S-lthonia,   143 

—  Syrian  143 

—  Tanglier,  133 

—  Trocas,   129,   134 
Steam,  superheated,  294,   143 
Steamer,  cargo  with  oil  fuel,  127 

—  recent  oil,   138 

—  tank  with  oil  fuel,  129 
Steel,  66 

Steel  tubes,  66 
Storage  of  oil,  228 

—  safety  moat,  228 

—  system,  G.E.  Rly.,  229 

—  tank,  oil,  228 
Stourbridge  clay,  67 

—  firebricks,  67 
Subweolden,  boring,  29 
Sulphur  in  oil,  36,  59 
Sumatra  oil,  49 
Superheated  steam,  294 
Supply  of  water,  84 

—  tank,  oil,  231 

—  system,  bunker  pipes,  137,  141 
Surcouf,  test  of,  177 
Swensson  atomizer,  256 
Syrian,  s.s.,   143 

System,  Aerated  Fuel  Co.,  267 

-  Baldwin  Co.,   178 

—  Billow,   195 

—  Clarkson-Capel,  218 

—  distribution,  228 

—  Ellis  &  Eaves,  222 

—  Flannery  Boyd,  136 

—  Fvardofski,  262 

—  Guyot,  254 

—  Holden's,   154 

—  Hoveler,  267 


System  Howden's,   133  143 

—  hydroleum,  214 

—  Kermode's,  208 

—  Korting,   143,  152 

—  Meyer,  172 

—  mixed,  37,  172 

-  National  Fuel  Co.,  195 

—  Orde's,   140,   143 

-  Pumping,  231,  198 

-  Rusden-Eeles,   134,   143 

—  Springfield,  269 

-  Symon  House,  257 

-  Urquhart,  184 

—  Wallsend  Slipway   Co.'s,    143, 

146 

T 

Tanglier,  s.s.,   133 
Tank,  car  hose,  201 

—  oil  supply,  231 

—  steamer,   138 

—  storage,  228 

—  underground,  230 
Tar,  41,  43,  47,  214,  237 

—  properties  of,  237 

—  water  gas,  test  of,  215 

—  shale,  47 
Temperature,  92,  284,  293 

—  calculation  of,   100 

—  flame,   112,  259 

—  furnace,  112 

—  of  combination,   101 

—  of  ignition,  82,  292 
Tender,  fuel,   186 

—  G.E.  Rly.,   165 

—  Grazi-Tsaritsin   Railway,   186, 

190 
Test  of  air  atomizing,  226 

—  Beaumont  oil,  57 

-  Borneo  oil,  208,  211 

—  Furieux,  175 

—  marine  boiler,  222-227 

-  Texas  oil,  56,  48 

Tests  at  Cherbourg,  175,  264 

—  at  Birkenhead,  212 

—  at  Indret,   176 

• —  Godard  boiler,  258 

—  Russian  oil,  37 
Texas  oil,  45,  51 

—  analysis,  48,  51 

—  calorific  power  of,  53 

—  carriage  of,  35 

—  chemistry  of,  48 

—  costs,  59 


308 


INDEX 


Texas,  density  of,  49 

—  efficiency  of,  56 

—  specific  gravity  of,  49 

—  tests  of,  56 
Thermal  units,  90,  294 
Thermo-chemistry,  90 
Thermometer,  93 

Thiele  on  Texas  oil,  45,  51 
Torpedo  boat,  38 

—  boiler,  French,  260 
Trinidad,  28 
Trocas,  s.s.,   129,   134 
Tubular  boiler,  underfired,  205 
Tunnels,  Railway,  171 
Tuyere,  air,  202 

U 

U  gauge,  239 

Underfired  tubular  boiler,  205 

Units  of  heat,  90,  97 

—  thermal,  97 

—  weight,  85,  98 

—  work,  98 
Urquhart  atomizer,   193 

—  locomotive,  191 

—  system,   184 

—  tender,  188 

Useful  figures,  87,  89,  292 


Vaporization,  heat  of,   106,   117 
Vaporized  liquids,  combustion  of, 

218 

Vaporizer,  273,  275 
Vaporizing,  43,  216,  218,  276 

—  carbon,  78,  79 

Variable   blast    pipe,    Macallan's, 

170,  240 

Varieties  of  liquid  fuel,  43 
Velocity  of  efflux  of  air,  238,  248 

—  draught,  237 

—  watqr  in  pipes,  88 
Ventilation,   128 
Verein-Deutsche  ingenieur,  91 
Violet  rays  in  flame,  120 
Volatile    constituents     of    petro- 
leum, 36,  39,  42,  47 

Volume    and    weight    of    atmo- 
sphere gases,  293 

—  gases,  289 

—  petroleum,   183 

• —  of  combustion  gases,  289 


W 

Wallsend  Slipway  Co.,   143,    146 

—  Atomizer,   148 

—  furnace  brickwork,  146 

—  latest  system,  149 
Warming  oil  fuel,  263 

War  vessels,  Sir  F.  Flannery  on. 

130 
Water  capacity  of  boilers,  24 

—  compressibility,  85 

—  data,  85 

—  expansion  by  heat,  85 

—  flow  of,  88 

—  gas  tar,  215 

—  gauge,  239 

—  hardness,  88 

—  in  oil,  68 

—  latent  heat  of,  84 

—  pipes,  88 

—  properties  of,  84,   294 

—  pure,  84,  294 

—  solubility  of  salts  in,  88 

—  source  of,  84 

—  specific  heat,  86 

—  supply,  84 

—  useful  data,  89 

—  weight,  87 

Water-tube  boiler,  Guyot,   176 

—  Hydroleum,  215 

—  Orde's  system  for  liquid  fuel, 

140 

—  Wealden,  29 

—  Weir's,  40,  121 

—  without  grate,   169,  206 
Weight  of  air,  82,  289 

—  gases,  289 

—  hydrogen,  81,  289 

—  firebrick, 

—  oil,  58 

—  oil  per  barrel,  58 

—  oil  per  gallon,  58 

—  oxygen,  84,  289 

—  nitrogen  84,  289 

—  water,  85,  294 
Weir's  boiler,   121,  40 

—  oil  pump,  231 
Welsh  coal,  117 
Williams  atomizer,  56 
Work  units,  98 
Wyoming  oil,  46 


Zante  oil,  49 


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